Word on the Street

Legislative Update

Ask Dr. Burge -- What Is the Difference Between Exposure and Dose?

Radon Corner -- Radon Mitigation Standards: Are We Overlooking Local Codes?

IAQ and Schools -- Look at HVAC, Sources to Settle Enduring Trouble

Labs and Testing -- Inter-laboratory Variability in Spore Trap Analysis

Contractor's Toolbox: Antimicrobial Products -- Robots to Replace Manual Application in Air Ducts
 

Progress Observed at Walter Reed’s Worst Building
By Steve Sauer

Two of Walter Reed’s military administrators and a spokesperson from the Army Medical Center’s public affairs office guided IE Connections on March 20 through a tour of vacated rooms, some of them newly restored and others untouched, at Building 18. The tour also included a walk on the roof, which had already undergone some minor patchwork but was going to undergo a full repair in the coming weeks, according to Master Sgt. Gary Rhett, building manager.

Evidence of water intrusion remains in the untouched room 416, where a leak from the ceiling drips onto a table below it. Elsewhere in the room is a water-stained lampshade. This room and all other occupant rooms inside the former hotel building were vacated late in February, after a series run in the Washington Post beginning on Feb. 17 depicted poor indoor environmental conditions and a trend of neglect mostly within Walter Reed’s Building 18.

The tour began in room 205, with the wall the Post had identified as full of “black mold” when it was occupied by a recuperating Army specialist. The Army had moved that occupant, Spc. Jeremy Duncan, to a new room after the Post notified them that it intended to publish the series. Six days after the first story appeared, freshly painted rooms in Building 18 were made available to reporters, but renovations would close the building to all occupants by the end of February.

Rhett offered IE Connections entry into any room inside the four-story building. When asked to provide access to a mechanical room at Building 18, the other military tour guide said there was no such area. “Because most of these [rooms] have in-room HVAC systems, there would not be a mechanical room,” said Col. Mike Doherty, who is Walter Reed’s director of safety, health and environment.

What Went Wrong

IE Connections: Is this building considered a hospital?
Col. Doherty: It’s part of the garrison.
Master Sgt. Rhett: It’s a dorm.
Col. Doherty: So, actually, we’re not under the control of Colonel [Virgil] Deal, the hospital commander. It comes under the control of Colonel [Peter M.] Garibaldi, who is the garrison commander. And then, it is essentially given to the brigade, who then manages the operations within the building because they’re the ones that are occupying it. Each building has a senior building occupant, or a building manager in the case of Master Sergeant Rhett here.

IEC: So then this building – is it actually exempt from hospital standards, JCAHO standards?

Col. Doherty: I believe it would be because you’re not performing any kind of treatment. JCAHO normally looks at treatment. Now if this were a nursing home, for example, that would fall under those kinds of regulations. It’s really essentially a dormitory where it’s, you know – with the caveat that the personnel here were primarily wounded warriors who were ambulatory, that could walk to their patient rooms.

Master Sgt. Rhett: They’re in the final stages of [their recuperation].

IEC: Was there such a thing as a baseline building study ever performed in here to figure out things like the direction of the airflow, pressure relationships between indoor and outdoor areas?

Master Sgt. Rhett: I don’t know of any, and I’m newly assigned as well. ...

Maintenance Contracts

IEC: February 4 was the official change in maintenance at the Medical Center. Did that affect this building? I believe that’s when IAP Worldwide Services stepped in.

Col. Doherty: On February 4, 2007, they then became responsible for the maintenance of all of the garrison’s buildings, with the exception of the hospital, the Armed Forces Institute of Pathology, and the Walter Reed Institute of Research – all of those have their own particular contractors for maintaining the building. They also have separate janitorial contractors. Yes, this building would then have been maintained, and minor repairs are done by IAP. Prior to that, it was the directorate of public affairs.

IEC: You made a distinction there with minor [repairs]. What about major repairs?

Col. Doherty: Major repairs, you’d have to contract out.

IEC: For instance, the roof.

Col. Doherty: The roof repairs, right. That brings in the Corps of Engineers because that’s beyond the scope of what IAP has to do. Even when DPW [directorate of public works] managed this, their workforce was primarily oriented toward building maintenance, with some minor repairs – usually up to about $2,500 and at a certain limit on man hours. Anything bigger than that ... For example, if somebody punched in a wall, that would be within the scope of what IAP or DPW would do. However, if a car crashed into the building and demolished a portion of it, you would bring a contractor in order to repair that.

IEC [pointing]: This hole in the wall ...

Col. Doherty: This could be done by IAP.

IEC: What caused the Army to want to seek out a private company to handle maintenance?

Col. Doherty: It was really a DOD [Department of Defense], congressionally mandated requirement under A-76, so it’s above our pay grades. It was not a decision by Walter Reed per se. It was mandated back in – I guess it was 2001 ... So, you go through all of these procedures to determine workload and everything else like that, [and] you arrive at an estimate for what the most efficient organization under the government would be. The contractor also determines what the workload is and what their existing staff and all this other sort of stuff would be, and then you come up with two estimates in cost. And it basically comes down to whoever the lowest bidder is at that point gets the award. I believe that the contractor had to achieve at least something like a 10 percent difference. ...

IEC: Is it true that in the last three years of getting this [maintenance] contract, “repairs went undone as the nonmedical staff shrank from almost 300 to less than 50”? That was – Associated Press reported that yesterday [March 19].

Col. Doherty: I couldn’t really say one way or the other since I work in directorate of safety, health and environment. DPW would probably have to address that. ... It is safe to say, though, that as this – once the announcement was made that a contractor would take over, a number of individuals began looking for work elsewhere. We were, however, authorized by Major General [George W.] Weightman [who had served as commander of the Medical Center until he was fired on March 1] to come up with a contract bridge that we could bring in under the Fed Source contract temporary people to fill the roles of those government employees who left. And in several instances, that was done. But I know that the workforce did shrink, simply because we couldn’t keep up with replacing those people that quickly.

IEC: Somebody mentioned to me the U.S. Army Center for Health Promotion and Preventive Medicine. They have staff in engineering and industrial hygiene [among other fields]. Was there anything that their personnel might have been able to do to assist in providing a consultation in environmental health risk?

Col. Doherty: Potentially, they could have. [Hands a stapled printout of the “Army Facilities Management Information Document on Mold Remediation Issues,” published February 2002.] This is the CHPPM technical guide on mold issues. We, on the environmental side, we utilize CHPPM for hazardous waste training. And so they could provide services like that. If a request had been made, yes. ...

Improving IEQ

IEC: What will the role of IAP be, or what is it now?

Col. Doherty: They’re still the base operations contractor. So when this building goes back online, it will be their responsibility to once again do the maintenance inside the building.

IEC: And then the [U.S. Army Corps of Engineers’] function is ...

Col. Doherty: They do the contract awards. They also will receive a contract, so when the roof contract, they would have an inspector who would come in and inspect the work, make sure it is done to the contract’s specifications. ... We do get unsolicited offers from time to time. I just got one from a company that is promoting ultraviolet light as a means of mold control, so things like that come in, but again, if I wanted to do that, I simply can’t go to that company, select them and bring them on board and do that. I have to go through a competitive process. So that, let’s say, a competing firm with a different – and we, we don’t always do scope of work anymore, we issue a performance work statement, which says the needs to conform to this level. I don’t, we’re no longer specifying it has to do this, this, this, this and this, in exactly that order. It says this is the performance standard you have to meet – I don’t care whether it’s ultraviolet light, whether it’s ozone, you know, whether it’s chlorine, you know. Whatever that standard is, this is the standard you have to meet to remain protective of human health in the environment.

IEC: Do you know what’s being done to fix the roof [at Building 18]?
 

Col. Doherty: I don’t know.

Master Sgt. Rhett: Exactly – they’re replacing the whole roof. I don’t know what materials are – we don’t have that information. ...

IEC: Do you know what the timeline would be for that, for fixing the roof?

Master Sgt. Rhett: We’re looking at approximately three or four weeks.

IEC: You said earlier that that contract was awarded through the Army Corps to some private company?

Master Sgt. Rhett: That is correct.

IEC: One of you addressed earlier about sampling that was done [in a second-floor room]. Do you know who actually did that?

Col. Doherty: We have an industrial hygiene section that can perform some sampling for that. They came in and did a survey on the first of March, and that’s [hands a one-page double-sided sheet dated March 12] the results of their survey. And of course a lot of things were done in the meantime. I also have under my control, the safety office, they did an inspection on the 26th of February [hands a one-page double-sided sheet dated March 9 that was clipped to 28 black-and-white photographs], and that addresses the findings they have which were, again, primarily oriented toward safety, so they dealt with more issues than just mold. They’ve since re-inspected this facility, and the deficiencies that were identified on the 26th of February have all been corrected. ...

IEC: In the actual mold removal work, would that be the same people doing that who were taking the samples?

Col. Doherty: Not necessarily, but if I were a contractor I would probably have someone verify, or I might bring an independent on board with them to make sure that the mold was removed. If I am made to meet a standard of no mold, how can you assess that you’ve met the standard unless you do some type of sampling? Unless it’s a visible requirement.

IEC: Are people following any standards in the mold removal process? For instance, there is an industry standard, the IICRC S520 that our readers are familiar with.

Col. Doherty: Can’t say I’ve heard of it, and I don’t know what the standard is that they’re following.

IEC: There’s also – the EPA has guidelines, and New York City has guidelines. [To

Master Sgt. Rhett: You’re nodding your head there for that.

Master Sgt. Rhett: There’s no choice in that matter. Those standards have to be met, so we’re going to get the appropriate people to handle that to a certain extent and to a standard.
 

Voices

“I am so impressed with this milestone event, and the subject matter as stated in the release, that I actually stroked a check and joined. I believe this is the most positive move I’ve seen within our Industry that I’ve witnessed since the Mold Rush of 2003, including the much ballyhooed Unification.”

— Pete Carkhuff, a regional manager with Emergency Response Solutions, describing how he feels knowing that industry organizations are breaking their silence to address the issue of conflicts of interests; his words were posted March 9 to the Internet discussion group Healthy Indoor Environments

Word On The Street

TWO HEARINGS REQUESTED OF S520 BODY

Carl Grimes, one of two former members of the committee revising the S520 mold remediation standard, has rejected the offer of an informal procedure toward resolving complaints about the standard-writing process he filed in December. His e-mail to a representative of the Institute of Inspection, Cleaning and Restoration Certification makes Grimes the second person formerly linked to the S520 Consensus Body to request a formal hearing before it to resolve complaints filed late last year. His message was sent March 22, two days after Grimes spoke with Larry Cooper, who represented the IICRC secretariat during a 90-minute meeting described as “cordial” and whose discussion was “both clear and informative.” Grimes, who is a member of the IE Connections Editorial Advisory Board, confirmed to the newspaper that he had chosen to pursue a formal hearing instead of accepting the conditions Cooper presented, which included submitting a fresh set of bullet points outlining his original complaints. He said Cooper’s approach at first appeared to be “a fresh start and a simplified approach” but that he later decided “the conditions were so restrictive as to make me complicit with their violation of ANSI procedures” to resolve an appeal. IICRC representatives did not comment by press time.

Another former S520 Consensus Body participant, Elisa Larkin, first requested a formal hearing on Feb. 11 for unresolved issues concerning an appeal she brought forth in November. As this issue went to press, Larkin said no hearing had been scheduled for her but that she and Cooper had recently scheduled a meeting to take place March 30 in Denver.

BILL SPONSOR BACKS INDEPENDENT MOLD CERTS

Certifications provided by independent certifying bodies and accredited by third parties are “crucially important” in attempts to improve quality of professionals providing mold-related services, Fla. Rep. Carl Domino said last month. His comments on industry quality certifications were delivered in an open letter addressing attendees of an Indoor Air Quality Association chapter’s statewide meeting held March 7–8. “I support the inclusion of such certifications as requirements for individuals performing indoor air quality services in Florida,” said Domino, who is the sponsor of a bill in the House of Representatives that would regulate mold professionals. He identified three components of a quality certification. “First, they verify the knowledge and experience of their candidates using credible instruments,” he said, giving as examples psychometrically qualified exams, documented field experience and board-awarding by industry peers. “Second, [quality certifications] are accredited by nationally recognized, third-party accreditation bodies,” he said. “Third, they are operated independently of training organizations and industry associations.”

Charlie Wiles, executive director of the American Indoor Air Quality Council and a member of this newspaper’s Editorial Advisory Board, said in a press release dated March 23 that Domino’s statement “goes to show that our work in raising the standards for certification in the indoor air quality industry is having an effect.” Wiles added, “We look forward to the day when credible certifications are relied upon to support licensing requirements in every state.”

STATE FARM TO RECONSIDER KATRINA CLAIMS

State Farm has agreed to reopen more than 35,000 insurance claims in Mississippi related to Hurricane Katrina upon policyholders’ request. A March 19 news release from the state’s Insurance Department said the insurer “intends to make millions of dollars available for additional payments to policyholders in Hancock, Harrison and Jackson counties,” the state’s three counties on the Gulf Coast. In the release, insurance commissioner George Dale said State Farm’s actions would be “in the best interests of Mississippi policyholders.” Terms of this new settlement are said to be similar to one a court rejected earlier this year, but the settlement with the state’s commissioner of insurance appears not to be subject to court approval. A statement the insurer’s spokespeople provided to reporters on March 19 compared the new settlement with an earlier one rejected by a court but avoids having to be approved by a court. “Unnecessary court battles and political rhetoric serve no one’s interest,” reads a passage widely quoted in media.

 

ASHRAE LAUNCHES FIRST CERTIFICATION

A program to certify healthcare facility design professionals is being launched by the American Society of Heating, Refrigerating and Air-Conditioning Engineers. The first examination to earn the credential is to be held June 28 in Long Beach, Calif., immediately following ASHRAE’s Annual Meeting there. Subsequent examinations will be Web-based at testing facilities nationwide. The HFDP certification will designate understanding of a body of knowledge identified by ASHRAE as being critical to successful facility design.

“An ASHRAE certification will let employers know that the certification earner has mastered a significant body of knowledge in a specific aspect of HVAC&R design, as determined by industry professionals in that field and has met specified eligibility requirements,” says ASHRAE President Terry Townsend. “Firms who employ ASHRAE-certified engineers will be better able to promote their services. This is an invaluable benefit to ASHRAE members to help them stand out from the competition.”

Persons interested in earning the certification must meet certain eligibility requirements and submit a completed application. Membership in ASHRAE is not required to participate. For more information, visit www.ashrae.org/certification or e-mail certification@ashrae.org.

Technical content for the certification exam was developed in conjunction with the American Society for Healthcare Engineering of the American Hospital Association. ASHRAE says it will work with other industry organizations to develop additional certification programs, including sustainability, commissioning, and building operations and management.
 

Legislative Update

CONNECTICUT

The stated purpose of Senate Bill 1051 is “to monitor the quality of indoor air in state buildings.” The bill would require the state’s Public Works Department to conduct a comprehensive inspection and evaluation of the IAQ for each state building before 2009 and every five years thereafter.

MAINE

The nonbinding Legislative Directive 20 directs carpet to be removed from all Maine schools. It was introduced Dec. 22 by Rep. Paulette Beaudoin, a first-term Democrat who represents the state’s southwest region, which has been home to various mold problems in schools.

Beaudoin can be reached by e-mail at RepPaulette.Beaudoin@legislature.maine.gov or by phone at (800) 423-2900.

Jenn Mendez, who is lobbying against the bill for the Carpet and Rug Institute, can be reached by e-mail at jmendez@carpet-rug.org or by phone at (703) 875-0634.
 

MARYLAND

Senate Bill 639 requires national and state criminal history records checks as a prerequisite to being granted a license in heating, ventilating, air-conditioning and refrigerating.

The bill is sponsored by Sen. Katherine Klausmeier, who can be reached by e-mail at katherine.klausmeier@senate.state.md.us or by phone at (410) 841-3620 or (301) 858-3620.
 

MINNESOTA

House Bill 402, introduced Jan. 29, calls for a study of whether the state should issue licenses for residential microbial pesticide applicators. It specifies that the study consider licensing programs existing in other states.

The bill is sponsored by Rep. Rick Hansen, who can be reached by e-mail at rep.rick.hansen@house.mn or by phone at (651) 296-6828.
 

NEW JERSEY

Four IAQ-related bills filed last year carry over to the current year in the state legislature’s two-year session.

Assembly Bill 973, introduced one year ago in January, calls for the Department of Community Affairs to establish its own mold remediation standards, a statewide certification program for mold assessors and remediators. It would also require the department to provide buyers and renters of real estate with information on mold-related state programs.

Assembly Bill 1015, also introduced one year ago in January, requires the registration of compensated mold inspectors and remediators according to the provisions of this act, including the annual submission of an application and registration fee.

Senate Bill 1249, also introduced one year ago in January, establishes a “toxic mold commission” that would be required to make recommendations for implementing a mold inspection program. The bill would also require mold inspections be conducted as a condition of real estate sales.

Assembly Bill 1787, introduced last May, establishes a “toxic mold commission” and also requires mold inspection as a condition of the sale of residential property.
 

NEW YORK

Assembly Bill 2006, introduced Jan. 11, would require that building owners develop and maintain an indoor environmental plan and respond to complaints about indoor air quality. The bill’s sponsor, Assemblywoman Donna Lupardo, can be reached by e-mail at lupardd@ assembly.state.ny.us or by phone at (607) 723-9047 or (518) 455-5431.

Senate Bill 1752, introduced Jan. 25 as the Toxic Mold Safety and Protection Act, provides for research on mold including standards for the prevention, detection and remediation of mold; public education on the topic; and housing provisions for the prevention and detection for indoor mold hazards.

As for research, the Department of Environmental Conservation would be required to conduct and submit “a comprehensive study on the health effects of indoor mold growth and toxic mold.” The study is to identify exposure levels and the hazards involved in mold remediation, methods for mold detection, and “detailed information about harmful and/or toxic strains of mold.”

The bill also requires the Division of Housing and Community Renewal to “study and report the impact of construction standards on indoor mold growth.”

Within a year of the above studies, the Department of Environmental Conservation would be required to develop standards for mold inspection, remediation and testing, and for the certification of mold inspectors, remediators and assessors, and for laboratories that test mold and industrial hygienists involved with the planning of mold remediation. Standards for the design, installation and maintenance of ventilation and air-conditioning systems “to prevent mold growth or the creation of the conditions that foster mold growth” would also be required. The legislation encourages participation from national organizations and requires draft standards to be offered for 30-day public review and comment.

The bill appropriates $250,000 toward the Toxic Mold Hazard Insurance Program, which would be created as part of the state’s insurance law.

The bill’s sponsor, Sen. John D. Sabini, can be reached by e-mail via his Web site, www.nyssenate13.com, or by phone at (718) 639-8469 or (518) 455-2529.
 

RHODE ISLAND

House Bill 5259, introduced Jan. 31, requires the health department to conduct annual IAQ inspections in public school buildings. The Committee on Health, Education and Welfare, which is chaired by bill coauthor Rep. Joseph McNamara, recommended Feb. 7 that the bill be held for further study.
 

Q. What is the difference between exposure and dose?
A. This is an important question. A lack of understanding of the difference between these terms has resulted in misinterpretation of dangers associated with fungal growth.

So, what do the terms mean? My definition for exposure is being in the presence of an agent long enough that it enters the body. Dose is specifically how much of an agent to which one is exposed reaches a site in the body where it can have an effect.

Generally, all of the steps in an environmental investigation are designed to evaluate exposure. That some dose of an agent actually is achieved is assumed (often inaccurately). Let’s go through an investigation and see where dose comes into the picture (if it does).

First is the visual observation. You see mold growing on a wall, and you assume that the mold is producing something (e.g., spores, VOCs, fragments, etc.) that could get into the air. You extrapolate from that to exposure by estimating how much time occupants spend in the space. If they are casual visitors, then you consider that exposure is low; if they occupy the space for eight to 10 hours a day, then you assume that more exposure could occur. In your mind, you relate this to the possibility of a dose of some mold agent sufficient to cause symptoms. You have, as yet, not actually documented that any exposure has occurred. If you have been hired to find the mold and remove it, this is probably enough information.

Second, you collect bulk samples. If you use microscopy or culture to analyze these samples, you can document that the mold is producing spores, and you can name the mold. This will give you some information as to the agents that could be present. It does not increase your knowledge of whether or not exposure is or is not occurring. If you analyze the bulk sample chemically, you may be able to pinpoint an actual agent (e.g., a specific mycotoxin or a specific allergen). This still does not provide any more information about whether or not exposure is occurring or how much.

Third, you collect air samples. If you use microscopy or PCR to analyze these samples, then you can estimate airborne concentrations of total spores (not particularly useful information), or you can calculate concentrations of specific spore types such as Stachybotrys or Alternaria. Combined with estimates of time spent in the space, breathing rate of the occupants, and spore size, you can estimate exposure to these spores. If the spore is produced by a potentially toxigenic fungus and you can find literature that tells you how much toxin is in each spore, then you can estimate how much toxin exposure the occupants experienced. You still don’t know the dose they received unless you know how soluble the toxin is, how fast it is metabolized and how fast it may be removed from the system.

If you use culture to analyze air samples, then you will usually have more accurate information on the species of fungi present but less information on actual concentrations. As with microscopy, the process of extrapolating to dose is a multi-step procedure that results in only a rough estimate of potential dose. If you analyze cultured samples for toxin, then you are documenting only that the captured fungus is capable of producing the toxin, not that it actually was producing toxin in the occupied space.
Finally, if you analyze air samples for toxin, then you come closest to being able to estimate dose. In this case, you know how much of a specific toxin is present and how long each occupant spends in the space. You don’t know the size of the particle on which the toxin was borne, and you still have to estimate dose in the ways discussed above.

Too often, the presence of a fungus such as Stachybotrys is assumed to mean that occupants were receiving a sufficient dose to cause symptoms. Unless you have thought through all of the above steps, this is somewhat like assuming a shark will eat you if you swim in your swimming pool. In order to prove such an assumption, you would have to document that there actually were fish in your pool, that the fish were sharks, that the sharks were man eating sharks, that they were big enough to eat you, that they were hungry, and that you couldn’t fight them off or get out of the pool in time.
Dr. Harriet Burge is director of aerobiology at Environmental Microbiology Laboratory Inc. and associate professor and director of the microbiology laboratory at the Harvard School of Public Health. Widely considered the leading expert in IAQ, Burge pioneered the field more than 30 years ago. She has served as a member of three National Academy of Sciences committees for IAQ, including as vice chair of the Committee on the Health Effects of Indoor Allergens.

To submit a question to Dr. Burge, write to her by e-mail at askdrburge@emlab.com. All questions posed to Burge will receive a reply, although space limitations prevent us from publishing them all. By submitting a question, you agree to have your question and its answer published in a future edition of IE Connections.

Many Local Codes Currently Address Radon Mitigation Practices

There are those currently in or entering the radon mitigation field that look to national standards as the sole means of defining acceptable practices. This misconception is perhaps perpetuated by the manner in which individuals entering this field are taught. An individual attending an entry-level mitigation course (with no prerequisites) is educated on the EPA Radon Mitigation Standards and tested on the content as a part of a certification exam. When provided a certification card, the person believes he or she has been given a license to mitigate with no further requirements.

However, there are a number of local requirements for contractors offering services to the public. The least of these is to follow local building codes!

Many individuals in the radon mitigation field would be surprised to learn that provisions of the codes are specific to radon mitigation. Some may even believe, mistakenly, that they are exempt from codes because Appendix F of the International Residential Code, which deals with the installation of radon systems in new homes may not have been locally adopted. What they don’t realize, at least where the 2003 International Mechanical Code has been adopted, is that Section 512 is specific to sub-slab soil exhaust systems, a.k.a., active soil depressurization radon mitigation systems.

Section 512 also specifies aspects of the International Plumbing Code that also apply to these types of systems. A quick review of this section specifies the following:

• Exhaust systems ducts shall not be trapped and shall have a 1 percent slope.
   
• System ducts shall extend through the roof and terminate at least six inches above the roof and at least 10 feet from any operable openings or air intake.
   
• System to be permanently labeled within each floor.
   
• By reference, specifies the type of pipe to be used that is more stringent than the EPA Radon Mitigation Standards.

Certainly, other aspects of the codes pertain to these systems – not the least of which is the method by which power is provided to fans, structural modifications, etc.

It is also interesting to note the following language that can be found in several current or proposed national standards:

• EPA Radon Mitigation Standards (Section 7.2): “Where discrepancies exist between provisions of the RMS and local codes or regulations, local codes shall take precedence.”
   
• ASTM E2121 (Section 5.3): “… contractors shall also conform to applicable local, state and federal regulations.”
   
• AARST Active Soil Depressurization Radon Mitigation Standards: “Where discrepancies exist between provisions of the ASD RMS and local or state codes that prevent compliance with the ASD RMS, the local or state codes shall take precedence.”

In other words, local codes take precedence, and their provisions apply now in many instances and will apply in the future if any of the proposed standards are put in place.

With respect to how widespread these codes are, a review of the International Code Council’s Web site indicates that the International Mechanical Code has been adopted in jurisdictions within 44 states and, more specifically, within over 1,100 individual jurisdictions. Given this widespread adoption of the IMC, the practicing mitigator would be advised to confirm how the local building department is handling Section 512 of the IMC.

 

Do Building Codes Offer Some Assistance to Radon Certification Programs?

Over the last several years, one of the recurring themes or comments at national radon meetings is that national certification programs should do a better job of policing the practices of radon contractors. This is especially true for states where no local certification programs exist and, hence, there is a reliance on the national boards. Without getting into definitions of certification and what kind of policing can be reasonably expected from nationally based organizations, the presence of local, enforceable codes could provide a partial solution to this concern.

Local code agencies exist for the purposes of protecting consumer safety in homes and other structures. They do this through permitting processes, contractors’ licenses and inspections. Furthermore, they have the infrastructure to do this on a local basis far better than any national credentialing body can and, most likely, better than a state-operated program can.

Local code agencies are also government bodies that have the ability to fine and prosecute individuals who do not comply with local codes and statutes. They also have the means by which actions can be appealed and reviewed. Local jurisdictions have the means to take action with a lot more bite than a voluntary credentialing program would have.

This is not to suggest that national certification is unnecessary. To the contrary, there are aspects of any profession that are not covered by prescriptive codes. In the case of radon, there is a need for business practices that deal with proper reporting, conflicts of interest and additional installation parameters that would go beyond the current building codes as needed (or until these can be incorporated into the code revisions). However, we do not need to wait for new codes such as Appendix F to be adopted when relevant codes currently exist.

The point of this column is to suggest that if we want better mitigation systems that are durable and safe, there is an alternative to creating more national standards. Radon standards could be significantly streamlined to build upon current codes and regulations, rather than attempting to replace them. Of course, this would have an impact on much of the current radon mitigation industry in that it would cause many to become licensed contractors prior to initiating their business (or perhaps even obtaining their national credential). It could also mean that permits and inspections might slow down the completion of a job. On the other hand, if we are serious about quality installations that are properly installed and do not present a larger hazard than the one that is being addressed, then that may be the price that gets to be paid.

As always, who says there is nothing new in radon?

Douglas Kladder is director of the Center for Environmental Research and Technology Inc. He can be reached by e-mail at dougkladdr@aol.com or by phone at (719) 477-1714.
 

William A. Turner, P.E.
President/CEO
Turner Building Science & Design LLC
Concord, N.H.

Steve M. Caulfield, P.E., CIH
Vice President
Turner Building Science & Design LLC
Harrison, Maine

We have been dealing with IAQ for 20-plus years each. That means we are getting old by some standards or wiser by others.

About 12 years ago, we had the opportunity to contribute to the U.S. Environmental Protection Agency’s Building Air Quality Guide, which we feel was a major step forward in assisting certified industrial hygienists and building facility operators in understanding how to approach and deal with IAQ concerns in non-industrial settings. In the face of unresolved concerns, a take-a-close-look approach often yields useful information that can assist with resolving concerns.

Recently, it has been somewhat of a surprise to us that some facility managers and industrial hygienists seem to think that if the numbers from random testing look normal, then they are done with the investigation or evaluation. That is, if the carbon dioxide numbers are OK, and if the thermal numbers look reasonable, and if the PM-10 (breathable dust) is less than 50 micrograms per cubic meter, and if the airborne mold spore counts (during short-term testing) are less than 1,000 spores per cubic meter, then they believe all is OK. Furthermore, they believe this indicates that we are doing the best anyone can expect to accommodate a teacher or office person who continually raises IAQ concerns; that is, the problem must be in their head, or they are just way too sensitive to work in the environment we can offer for them.

But this cannot and should not be the end of the investigation. In fact, a more logical starting point may be to look at the equipment.

Acceptability criteria: You all likely know and understand by now that there are few specific federal laws that specify a battery of acceptable parameters for air quality in non-industrial exposures. Design and operation standards and guidelines by the American Society of Heating, Refrigerating and Air-Conditioning Engineers are most frequently cited when dealing with non-industrial settings.

The typical diagnostic test result numbers look reasonable for IAQ upon data-logging for a week or more if:

• the carbon dioxide numbers are between 700 and 900 parts per million and decrease at night or when unoccupied;
   
• the carbon monoxide numbers are below three parts per million;
   
• the PM-10 Dust levels are lower inside than outside during the occupied period;
   
• the thermal comfort logging suggests typical temperatures of 70–74 degrees Fahrenheit, and relative humidity of 30–55 percent; and
   
• the short-term mold spore counts indoor are less than outdoors and mostly the same species as outdoors.

If all of the above is true, then one could suggest there are no obvious problems upon first look. However, the investigation or observations are certainly not over at this point if the concerns and complaints continue. This statement is especially true if the occupants have been complaining for multiple years and this is just another spot or week-long look at possibly the same situation that has been going on intermittently for a long, long time.
 

What’s Next to Consider?

Likely, a couple of things:

History and sources: One could carefully review the history of complaints and what was done to address them, other than standard testing that likely did not reveal too many problems. Or maybe there are new or recurring problems. Useful clues could be found by asking questions like: Is there a history of musty odors or any other odors that occupants notice? Are there short or long term foul odors like sewer gas, or boiler/gas/diesel smells? It is often useful to look for things that would not show up with standard CO2, CO, PM-10, airborne mold spore counts, and thermal diagnostics.

Are there known chemical irritants or microbial reservoirs anywhere to be found in the immediate vicinity of the concerned individual, or within the facility anywhere near this person or this group of people, or near the air intakes that serve these areas? Classic, often overlooked indoor sources include high-use photocopiers or printers, sewer gas leaks, and HVAC condensate pans and drains in hard-to-access, above-ceiling mounted equipment such as water source heat pumps. Other classic issues include grease traps and those traps that serve art or science rooms.

Classic, outdoor overlooked sources include short-height boiler stacks or other rooftop air discharges such as sewer pipes, and also nearby rooftop air intakes or nearby manhole covers over sewers, and operable windows nearby.

HVAC operation: Perhaps the first step in some of these investigations should be to take a really careful look at the HVAC system serving the area. Start with the outside air. Do the outdoor air intakes really open, and under what conditions do they open, and how much? Are they open too often and causing excess dryness in the winter? Does their operation change as part of a freeze protection system? Are the rooftop air intakes pulling air from immediately above a dark-colored roof? Have the air filters been good ones – minimum-efficiency reporting value of 8 or slightly more and two inches thick so that they cannot be seen through easily? Have they been maintained well? Are the controls working as designed? Does the building operator really understand what he or she is supposed to do? Does someone know for what the space usage was originally designed where the complaints are occurring?

Is the boiler room somehow impacting the air in the facility via adjacent walls or connecting metal ceiling flutes? Did someone actually design an air handler to be located within the boiler room, not understanding this can’t work? Is the air supply to the area or exhaust from the area somehow mining soil gas or air from a below-floor pipe trench?

Knowing how air gets to the room in a planned manner and unplanned manner is likely key in understanding if short-term, non-measurable exposures to irritants are occurring.

HVAC hygiene: Is there a condensate drain pan, and is it clean – or at least clean enough that you wouldn’t mind eating your lunch out of it? Is there some type of preventative maintenance on the condensate pans and drain lines in the above-ceiling water source heat-pumps, as well as the rooftop or built-up units?

What does the acoustical liner in the HVAC unit near the condensate pan look like: clean, moldy, falling apart, or missing? Where does the condensate drain line go: to a not-so-great-smelling area? Is it clean and reasonably nice-smelling wherever it goes; i.e., what is the actual construction of the condensation drainage system? Does the heat pump suck foul material from the drain line if the trap dries out, or does it somehow blow air into the drainage system where it shows up someplace else?

Additional Diagnostic Tools

Particles: One can tell a lot about what is going on with the use of a continuously running laser particle counter. It, along with some wind direction data, can likely reveal the impact of boiler emissions, either from the roof or via internal conveyance. Knowing the size, distribution and periodic nature of particulate goes a long way toward identifying a source.

Pressure mapping and tracer testing: One can often understand where air comes from and goes to by doing pressure diagnostics at each door with a digital micromanometer. It, along with tracer gas testing or use of tracer smoke, can often solve pathway identification challenges.

Problems resolution: So long as the complaints and occupant concerns continue, one needs to expend reasonable efforts to rule out irritants and exposures that likely would not be picked up with routine parameter monitoring. Although limited sampling that shows results within “acceptable levels” is a good short-term feel-good result, it does not get you any closer to resolving the real issues causing the complaints.

William A. Turner, P.E., is president and CEO of Turner Building Science & Design LLC. He has more than 25 years of experience in IAQ/HVAC evaluation and development of solutions for building system problems. He supervises a group of engineers, industrial hygienists and building scientists who serve owners, architects, general contractors and construction managers. Turner can be reached by e-mail at bturner@turnerbuildingscience.com or by phone at (207) 583-4571 ext. 11.

Steve M. Caulfield, P.E., CIH, is senior vice president of Turner Building Science. Caulfield can be reached by e-mail at scaulfield@turnerbuildingscience.com or by phone at (207) 583-4571 ext. 14.

 

Some indoor environmental consultants justify ignoring the issue of the analytical error in spore trap analysis, claiming that the “normal” variation in the concentration of total mold spores in the air far exceeds the variation introduced at the laboratory. This assumption is not based on the scientific research. It is also inconsistent with published, long-term microbial studies of controlled indoor environments. Granted, there can be a large variation in indoor mold spore concentration when mold spores are disturbed, but most monitoring is done prior to or after mold spores have been disturbed.

Spore trap analysis is highly dependent upon the visual skills of the microscopist in both identifying and quantifying the mold spores and other materials. In fact, this source of error is probably most significant. If the analyst misidentifies or undercounts the mold spores, misinterpretation and erroneous conclusions could be drawn from their analysis.

How significant is this spore trap analytical error issue? Testing this question is difficult. It is highly dependent upon the level and types of mold spores in the air. If one has low levels of big spore genera, it is easy to count the slides. Conversely, if one has high levels of small spore genera, it can be very difficult and time-consuming to adequately count the slides.

An interesting aspect of this counting question is that many commercial labs typically allow the microscopist six to eight minutes to count a spore trap slide. Ironically, for counting fibers for asbestos monitoring, which is much simpler, NIOSH specifies at least 10 minutes for counting each slide.

This research study has concluded that a majority of the SAE is a result of analytical error at the laboratory, not sampling error on the jobsite.

Spore Trap Counting Variability Research Project

During the summer of 2006, my company encountered an environment that was contaminated with mostly Aspergillus niger. These spores are relatively small, which makes them an ideal test for lab counting variability. The presence of Aspergillus niger was identified in the first round of sampling that included four culturable air samples and four total mold spore samples.

The building owner allowed us to come back and do a second round to evaluate the question of inter-laboratory variability in spore trap counting methods. He was not occupying the space and had an interest in research. At the same time, a number of laboratories agreed to volunteer their analysis services. Without the help of all these companies and individuals, this research would not have been possible.

In this research project, four spore trap sample slides were prepared and read by the first laboratory. These same four slides were then sent to six other laboratories starting in August 2006.

This research evolved into two projects. This first project focuses on analysis error, and identifies the laboratory variation in the analysis results. A second research project will focus on sampling error and collection efficiency of four different spore trap devices including the Air-O-Cell, Micro 5, Allergenco-D and Cycle D spore traps. Analysis of 28 samples for the second project is still in progress.

After the initial mounting and analysis of the four slides in this first project, each laboratory knew it was doing a recount as part of a research project. It is therefore likely that they used a more experienced microscopist to count these slides. In fact, if I ever send a set of slides for a second opinion, I would expect the second laboratory to use a more experienced microscopist.

Each volunteering laboratory had a different report format. Some included additional analysis for algae, hyphae, insect fragments, etc. The comparable analysis data for particular mold genera were extracted from the various lab reports and are shown in Tables 1 through 4.

As one can see in the tables, there was considerable variation in each analysis of the spore traps. Not only was there significant variance in the counts, but there was differing interpretation as to the identification of the genera.

For example, some labs identified some of the less frequently found spores while others did not. The only mold genera for which there is fairly consistent data from all six labs are Cladosporium and Penicillium/Aspergillus-type spores.

Obviously, the high variability of the data indicates that many complex factors are involved in spore trap counting. For example, where the microscopist views the trace appears to make a difference. In Table 2, two labs found some Trichoderma. It appears this genus was only in one spot on the trace, and these two labs happened to view that portion of the trace. A similar condition appears to have been present for Nigrospora in Table 3.

Realistically, there is so much variance in this data that little statistically useful information can be gained by a detailed analysis. However, some limited information can be gained by simplifying the information in the tables.

The first simplification that we can make in analyzing these results is just to look at the number of spores counted, rather than the concentration of spores in the air. We can do this because the sample volumes were all equal. The volume of air sampled is just a mathematical adjustment to the actual spore counts.

The second simplification would be to initially analyze the variability in counting the most common or frequently encountered mold spores, such as Cladosporium and Penicillium/Aspergillus-type spores. The assumption here is that since these are the most common genera encountered by the laboratories, the variability in identification and counting should be less than for other genera.

These two simplifications were used to develop Tables 5 and 6. Table 5 shows the Cladosporium spore counts for all four slides, while Table 6 shows the Penicillium/Aspergillus-type spore count data for all four slides. Each table also shows the statistical parameters of the average spore count and the standard deviation. The standard deviation is a statistical measure of the variance in the data.

Lastly, the standard deviation is shown as a percent of the average. This is known as the relative standard deviation. For a normal distribution, the relative standard deviation is 33 percent of the average. Here, the relative standard deviation is at least 50 percent of the average. Therefore, the data are not normally distributed.

For a normally distributed data set, adding or subtracting one standard deviation from the average of a data set will give you the numerical range for 66 percent of the data. Adding or subtracting two standard deviations from the average will give you the numerical range for 95 percent of the data.

For example, for sample 1 in Table 5, the average Cladosporium spore count is three spores. Adding one standard deviation to the average gives a maximum spore count of 4.5, while subtracting one standard deviation from the average gives a lower spore count of 1.5. This means that 66 percent of the lab counts were between 1.5 and 4.5. Adding two standard deviations to the average gives a maximum spore count of 6.0, while subtracting two standard deviations from the average gives a lower spore count of 0. This means that 95 percent of the lab counts were between 0 and 6.0.

What this research is trying to quantify is that given a specific laboratory result, how much variation in that number can be expected? For example, based on Table 5, should the laboratory then report Cladosporium results as plus or minus 50 percent? Further, based on Table 6, should one report Penicillium/Aspergillus results as plus or minus 72 percent?

So, which lab result is actually correct? Is a higher spore count the most accurate, or is it possibly misidentified and over counted? For example, the uniqueness of Cladosporium spores makes misidentification unlikely. A number of other factors can lead to higher spore counts, probably the most significant of which is whether the slide was examined at 400× or 600×. There is good scientific evidence showing that increasing the level of magnification during examination of a spore trap slide will yield higher spore counts.
A second factor is the wideness of the field of the objective lens of the microscope. With a wider field, the microscopist can see a larger area and, hence, more spores.

A third factor is that most labs read about 25 percent of the trace and then multiply that count by four to estimate the total count on the trace. Many also read up to 100 percent of the trace looking for genera with a single-digit spore count. Reading more of the trace can result in more accurate, higher counts.
A fourth factor is the visual acuity of the microscopist. Some people are able to see finer detail because they have more cells in their retinas. Fifth, experienced microscopists are more likely to properly identify and count spores than novice readers.

Could one have sent these slides to a laboratory and had the whole slide counted to get the “correct” count? At what magnification, etc.? The problem with having this done is that it is not a normal analysis method. This project was to see how much variability exists in the methods currently used by laboratories.

Based on this data, one could draw the conclusion that, most of the time, spore counts are undercounted. This would mean that one should typically report Cladosporium results as possibly being up to 50 percent higher and Penicillium/Aspergillus results as being up to 76 percent higher. In our data, this assumption was accurate half the time.

Clearly, this research raises serious and significant questions about using only spore traps to evaluate and classify the mold spore character of an environment. It also raises serious questions as to the scientific accuracy of using only spore trap data in legal cases.

Recommendations for Indoor Environmental Consultants and Analysis Laboratories

Based on this research, a few recommendations for consultants and analysis laboratories are provided below:

1. Laboratories should offer a “replicate” spore trap analysis service for legal cases. This service would use two microscopists to evaluate each spore trap slide. The results of the two microscopists would then be reported as a range. This would better quantify the variance associated with visual identification and give the IEP higher confidence in the data.
    
2. Laboratories should consider establishing a special “recounting” or “expanded” counting service. This service would involve counting a much larger portion of the slide. For example, one technician would read one area, and the other technician would read a different area. A much greater portion of the trace would be read in this manner. The special analysis results would be reported with a variance (e.g., plus or minus 25 percent) for the counts for each genus.
    
3. Laboratories should notify clients whenever clusters of spores were present. In this study, one lab reported clusters as potentially being the reason for such high variability amongst the labs. Clusters provide one of those time consuming counting challenges. Also, clusters can be broken up in Andersen samplers and result in higher reported culturable levels.

Lastly, we have undertaken a much broader study in the variability of spore trap counting along with various types of spore trap samplers. This study involves 28 slides taken at three different spore concentrations with four different types of spore trap media. The results of this research will be published later this year. If you are with a laboratory that wants to participate in this study, please contact me.

Dr. Bob Brandys has served as president of his own environmental consulting firm since 1984 and has authored numerous publications on chemical safety and microbial control for the hospital and healthcare manufacturing sector as well as the mold consulting and remediation industries. He can be reached by e-mail at bobb@safety-epa.com or by phone at (630) 325-2083.
 

Robots to Replace Manual Application in Air Ducts

Lance Weaver
President, Chief Operating Officer
Lloyd’s Systems Inc.
Rapid City, S.D.

Bernt Askildsen
Marketing Director
Lloyd’s Systems Inc.
Rapid City, S.D.

Antimicrobials play an important role in public health and safety. While providing health benefits of pathogen removal as well as duct liner preservation, the same antimicrobials involve risks of potential efficacy failure and exposure hazards. This is why the effectiveness and proper use of these products are of widespread concern.

To ensure proper application of antimicrobial products, contractors should be in compliance with any safety and regulatory requirements. Therefore, it is important to make sure that the antimicrobial action has been approved and registered by the U.S. Environmental Protection Agency or is covered by an exemption from registration for use in HVAC ducts. In this regard, note that any pesticide originally registered before November 1984 has to be reregistered, thus older EPA-issued documents may no longer be valid.

Duct systems are designed with materials that do not support microbial growth as manifested in the Underwriters Laboratories 181 standard. However, as dirt and organic matter accumulates in the ducts over time, the situation dramatically changes. Such buildups are perfect food sources for microbial growth when combined with high moisture levels. Fiberglass lined duct is usually more prone to dirt buildup than galvanized just because of the holding capacity of the fiberglass blanket. However, even galvanized duct will support microbial growth if enough organic matter is available.

With more than 100,000 mold species in the world, it is no wonder molds can be found everywhere. In nature, mold plays a key role in the decomposition of leaves, wood and other plant debris. Without mold, everybody would be wading neck-deep in dead plant matter. Due to the wide diversity of mold types, there are molds that can grow on wood, ceiling tiles, wallpaper, paints, carpet, gypsum wallboard and insulation, to mention a few.

A microbial problem first arises when more than one mold species starts digesting organic materials indoors and they release toxins when attempting the fight off competing mold species. Realistically, there is no way to rid all mold and mold spores from a building. The best defense is proper maintenance that includes a combination of changing filters, moisture control, source removal of any potential food sources and antimicrobial treatment. If a proper maintenance plan is followed, the probability that microbial growth will occur even in environments with permanent high moisture content, is very low.

Productivity

Productivity can be dramatically improved by working smarter and not harder. Today’s robots allow cleaning and antimicrobial application in sections up to 200 feet, or about 60 meters, between access openings such as preexisting fire-damper doors or other access holes such as those required for manual cleaning and spraying of turning veins. This range significantly reduces the labor need of cutting and patching approximately 50 access holes that is required for manual cleaning and antimicrobial application of a duct 400 feet long.

A quick work-study of such duct system comprised of 15×30 inch insulated duct shows that proper preparation, cutting and patching of each access hole takes approximately 30 minutes. Furthermore, manual cleaning and application take approximately 200 minutes each for the same 400-foot section. Thus, the manual approach requires a total of 32 man-hours to complete the job.

In contrast, newer design robotic systems may provide 20 feet cleaning per minute and 40 feet spraying per minute. With a total setup time of less than one hour, the same job takes approximately three man-hours from start to finish, reducing the total labor by at least a factor of 10.

If the cost per man-hour is $20, then the manual procedure is $640 compared to $60 when using robotics.
In order to reap these benefits, it is very important to assess what robot to use, as some of the older robotic technology can be quite inefficient. One-pass application robots are superior in performance and are the ones used in the above cost study.

As EPA-approved antimicrobials with additional material preservation benefits cost $30–40 per gallon, significant cost savings can also be achieved by using the same one-pass application robotics. For example, several studies have shown chemical savings of approximately 30 percent when applied robotically versus manually. Using these numbers with the previous cost study for the 400-foot duct section, manual application would require approximately 21 gallons versus 16 when applied robotically.

Considering a popular antimicrobial coating for HVAC ducts, the savings for this small duct would be $200. Comparing the cost of the two approaches, the difference of $780 translates into a total savings of $1.95 per linear foot for 15”×30” ducts. Cleaning and spraying only 5,100 linear feet of ductwork can therefore realize the return of investment of a robot costing $10,000.

Ergonomics studies have verified that muscle fatigue is significant when individuals work overhead during manual cleaning and antimicrobial application in HVAC ducts. Fatigued muscles make it impossible to keep arms raised overhead for even short periods of time. This makes reliable performance calculations more challenging, making each job susceptible for cost overruns. Contractors using manual cleaning and spraying methods should allocate an additional quality-control person responsible to verify that all cleaning and application have been properly completed. The rationale behind this is that persons who experience muscle fatigue have reduced motivation to complete the task properly. Furthermore, fatigued muscles increase the risk of labor-related injuries as addressed under safety.

Quality

Quality guarantees for the customer should be the main objective for professional contractors. In this aspect, the main objective should first be to ensure proper source removal before properly executing the antimicrobial application. A robotic system enables a contractor to view and digitally record both the cleaning and application sequences for real-time quality assurance and customer documentation. Spraying or coating lined duct manually requires many new access openings, and each opening creates a new frayed edge in the fiberglass liner. So, even though the microbial problem has been successfully addressed, a new hazard has been created where fiberglass particles are now continuously released into the indoor air. Various countries have recommended exposure limits that typically range from 1.0 to less than 0.5 fibers per cubic centimeters based on an eight-hour workday.

Furthermore, an increased number of access holes will create more turbulent airflow and, therefore, become new areas that will accumulate dirt and debris. All of these new openings, especially if improperly sealed, will cause increased air leakage from the duct system over time. These factors could significantly affect the energy efficiency of a building. When more scientific studies become available, it is possible that building owners will file civil lawsuits against contractors who have severely damaged the duct system’s integrity in a building.

According to UL 181, fibrous glass duct systems, when installed according to manufacturer’s recommendations, are virtually leak-free before the access holes are cut. Building owners may sue to recover energy losses and maybe even for the entire duct replacement cost if the damage is severe enough.

Robotic cleaning and coating, on the other hand, offers a secondary benefit to building owners. Coating tends to smooth the surface and seal air leakage, providing a more energy-efficient duct system. This provides an additional financial benefit to building owners in that energy savings may pay for an aggressive maintenance program. Tests are underway that will quantify the energy savings related to general duct-maintenance procedures.

Robotics allow access to ducts over inaccessible areas such as gypsum wallboard, plaster ceilings or those ceilings high over atriums. In these cases, robotic is the only method that can accomplish the objective with guaranteed quality assurance. Furthermore, using robotics, the contractor avoids uneven application. This translates not only into wasted chemicals as described earlier, but also into longer drying time and increased release for volatile organic compounds.

Robots exist that enable proper cleaning, spraying, coating and/or sealing of square, rectangular and circular ducts from 6×8 inches to 48×48 inches. Duct that is larger than 4×4 feet can be cleaned and coated manually if no confined space issue exists and the system is properly structurally supported. For ducts smaller than 6×8 inches, the most effective method for cleaning and application of antimicrobials is still manual.

Safety

Safety issues are and will be even more prevalent in the future as better scientific knowledge becomes widespread. It will be easier for employees to prove that their employer acted with intent, exposing them to unacceptable hazard levels. This, in conjunction with the government’s increasing enforcement of machine safety, falls from elevations, and chemical exposure standards will continually increase employer liabilities. This applies to all occupational areas concerning contactors providing cleaning and antimicrobials application to HVAC ducts.

Reducing the excessive access hole cutting required by manual cleaning and application can minimize machine safety liabilities. There are three main methods of cutting sheet metal:

1. Shears are efficient, but they leave a dangerously sharp edge, which is a significant safety hazard.
    
2. Circular access cutters operate as a drill bit of varied diameters and make a more smoothly cut edge compared to shears, but the hot dangerous metal chips created are extreme eye hazards.
    
3. Nibblers are the fastest cutting device and leave the smoothest edge, but these also produce small crescent shaped metal chips that are extreme eye hazards too.

Many eye and cut injuries are reported yearly due to the exposure during sheet metal cutting. Therefore, robotic techniques that eliminate the need for many access holes provides the best worker compensation insurance.

Any unprotected side or edge that is six feet or more above a lower level should be protected from falling by the use of a guardrail system, safety net system, or personal fall arrest system. These hazardous exposures exist in many forms. From changing a light bulb with a step ladder to something as high-risk as connecting bolts on steel beams 200 feet in the air. These requirements make it challenging if the ductwork is more than 12 feet above the floor. The cost of a duct cleaning and antimicrobial spraying job increases exponentially with widespread secure scaffold or ladder entry points. To reduce these risks and costs, robotics can get the job done with only a few elevated scaffold or ladder entry points, and the robot operator can work from the floor.

Recommended or mandatory occupational exposure limits have been developed in many countries for airborne exposure to gases, vapors and particulates. The most widely used, threshold limit values, are issued by the American Conference of Governmental Industrial Hygienists. The purpose of such limits for antimicrobial application is to avoid harmful aerosol particle exposure when using paint sprayers for manual application. To stay safely under the limits, respiratory protection should be used in conjunction with capturing those particles that would otherwise escape into the building space. Robotics solve this occupational exposure limit hazard as the duct is under negative pressure from HEPA-filtered negative-air machines. Also, there are very few access holes where exposure may happen. Furthermore, a significant distance between the robot’s spray nozzle and the operator ensures no direct exposure.
 

Conclusion

Trends in indoor environmental robotics show a dramatic change as small handheld digital video displays with standard SD card recording systems rapidly replace the previous generation of bulky systems. Many of the previous generation’s systems have large TV monitors and VCRs that require two people to set up and operate, whereas newer systems provide a dynamic capability whereby one system may be used for inspection, cleaning and application of antimicrobials operated by one person.

Furthermore, increasing focus has been on autonomous operation that significantly simplifies the operator interactions with the robotics and minimizes operator error. Autonomous operation allows the robot to automatically self center in the duct, adjust travel speed and raise or lower the spray head to ensure even application of antimicrobial coating.

Robotic cleaning and antimicrobial application can now be executed in ducts from 6×8 inches up to 4×4 feet providing a powerful video guided platform that document the work process and expose any internal issues of the HVAC system. Some vendors have already announced similar solutions for smaller ducts and for vertical chases. The availability of complete suites of video guided HVAC maintenance procedures will significantly improve delivered quality to the building owners thus provide better indoor quality for its occupants.
 

Lance Weaver, president and chief operating officer of Lloyd’s Systems Inc., has been pioneering robotic technologies for IAQ purposes for over 15 years. Bernt Askildsen is responsible for the corporation’s domestic and global marketing strategy. They can be reached by e-mail at info@lloydssystems.com or by phone at (800) 872-8753.