Indoor Environment Connections Featured Writer
Air Quality, Energy Conservation Go Hand In Hand  
by Mike Schell, Director of Marketing and Business Development, Telaire

As I sit here in California writing this article I have a strong sense of deja-vu. You see we all of a sudden have an energy crisis where electrical costs (already some of the highest in the country) have now tripled in some areas. Rolling blackouts are forecasted because our newly deregulated power providers are on the verge of bankruptcy.

As a result, newly created electrical wholesalers (the progeny of electrical deregulation) will not sell power to California utilities. Utilities and government are now scrambling to find ways to reduce energy usage. I know you are thinking "Well ain't that tough for California!" But remember, we fruits and nuts tend to lead the trend regardless of whether it is good or bad.

An Opportunity For The IAQ Industry

For those of us involved in indoor air quality, the energy crisis can present an opportunity. Many air quality issues can be directly related to building operation and maintenance, which by no coincidence also affect building energy consumption. Dirty ducts probably indicate clogged cooling coils that result in poor energy transfer. Clogged filters can reduce airflow, decrease cooling distribution performance and decrease cooling efficiency as a result of icing on coils. The lack of maintenance can result in non-functioning equipment, broken damper links or boarded-up air intakes that are never found. In one job, our company was involved in we discovered that a project to upgrade and enhance the façade of a conference hotel had inadvertently covered over outside air intakes. The only indicator that something was wrong was the elevated CO2 level in the space. We found out later that the company had instituted a "run it until if fails" maintenance program.

Many of our customers who buy our company's CO2 sensors to characterize and control ventilation based on occupancy (called demand controlled ventilation) find that the entire mechanical system often has to be repaired and re-commissioned before effective CO2 control can occur.

In many buildings we have found that well-meaning building operators have arbitrarily set air intake dampers based on their "feel of the building" which inadvertently leads to over ventilation. Over ventilation can also occur if an operator translates the 20 percent outside air rule of thumb for a building to a 20 percent open setting on air intakes. Unfortunately damper position typically has a exponential relationship to ventilation rate and a 20 percent open position could result 40 percent to 60 percent outside air.

Over ventilation obviously affects energy consumption but it also can negatively affect indoor air quality. For example, if this over ventilation occurs on humid days it can overwhelm the moisture removal capability of the cooling system resulting in water condensation in unwanted area. Water condensation then provides a catalyst for mold and microbial growth. These are only a few examples of the relationship between building operation and maintenance, energy use and indoor air quality.

One of the most compelling arguments for considering the relationship between indoor air quality and energy savings is money. If a building performance improvement can generate a quantifiable cost payback in under two years in terms of lower energy bills the decision to proceed is generally a no-brainer for a building owner. If the same improvement also improves air quality and provides less tangible but real impact on productivity and health, all the better! Rather than reacting to a negative issue of "indoor air quality" a building improvement can be positioned as and improvement in economic performance.

Energy Conservation

The best example I can provide on this relationship between indoor air quality and energy conservation is the use of CO2 based demand controlled ventilation (DCV). This is an approach where a building control system uses the CO2 level in the space to calculate and control to code required cfm/person ventilation rate to the space based on actual occupancy. This is in contrast to the more arbitrary and traditional method of ventilating at a fixed rate based on a assumed maximum occupancy (occupancy X target cfm per person). Real and quantifiable energy savings can result from this control approach by reducing unnecessary over ventilation that may result from varying occupancy or improperly adjusted air intakes.

Importantly a space level CO2 measurement can also measure and control the efficiency of outside air distribution to different spaces in a building. A flow measurement at the building air intake can tell us if the right amount of outside air is being provided to a building, but space level CO2 monitoring can indicate if outside ventilation air is actually being provided to the spaces in proportion to occupancy. Carrier Corp. has been one of the first to offer zone level CO2 control to modulate a variable air volume system for both temperature and ventilation control. The logic in the system integrates control of individual zone VAV boxes with the building central air intake to ensure the right amount of outside air is delivered to all spaces. Target cfm/person rates can be assured but the system more effectively controls the amount and distribution of outside air to save energy and money.

The downfall of many energy conservation initiatives tried in the past is that it is often difficult to quantify or verify what energy savings will be. Many utilities scaled down their rebate programs a few years ago when they discovered that many initiatives were not generating the payback expected. The initiatives that are the most popular today are the ones that can provide predictable energy savings. Lighting retrofits are popular because of their predictability. Replace a light and ballast with one consuming less power and energy savings result.

CO2 Monitoring To Determine Potential Energy Savings

For demand controlled ventilation, initial characterization of a space with CO2 monitoring can determine current space ventilation conditions and allow determination if a space is over ventilated or under ventilated. If over ventilated, CO2 monitoring can actually quantify the degree of over ventilation and use this to calculate energy savings. Contractor, building owner and utility risk are all reduced if current conditions can be determined before a installation begins. It is important to note that even if a space is under ventilated, CO2 DCV may be the most economical approach to bring the building up to desired ventilation levels.

Most CO2 sensor manufacturers provide guidance or built in capabilities in translating CO2 levels to ventilation rates. There are also a number of technical papers published in the past year that also document this procedure. ASTM has also published a standard on how to use CO2 to estimate ventilation rates (ASTM Standard D62-45-98).

Once the ventilation rate is known, an estimation of energy savings can be made by calculating the ventilation required for DCV versus the measured ventilation rate using CO2. Such a calculation should include local climatic data to estimate the cost of heating and cooling outside air and local energy prices. Many utilities also look for impact on peak demand reduction. Engineering energy analysis programs such as DOE II can be configured to do this type of analysis. Many utilities may also have their own programs for calculating these type of savings. Both Carrier and Telaire also offer a software tool for estimating the energy impact of CO2 DCV on a building.

Follow The Money

If you want to improve your building performance and grow your business all you have to do is follow the money. The money today is in energy conservation. Energy conservation is a financial tool that can be used to justify building upgrades that impact indoor air quality. CO2 monitoring and control is just one example.

Mike Schell is director of Marketing and Business Development for Telaire, a leader in the manufacture of low cost infrared CO2 sensor for ventilation assessment and demand controlled ventilation. You can reach him at (805) 964-1699 or by e-mail at mike.schell@telaire.com.

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ACGIH Defeats Lawsuit To Halt TLV 
by Glenn Fellman

Just days before the American Conference of Governmental Industrial Hygienists, International (ACGIH) was scheduled to publish a TLV of 0.2f/cc for refractory ceramic fibres (RCF), a trade association of RCF manufacturers filed a law suit in the United States District Court in Atlanta, Ga., and asked the Court to issue a temporary restraining order that would bar ACGIH from publishing the TLV.

RCF is an asbestos-like material used principally as an industrial product for insulation, reinforcement and fire protection of industrial furnaces, heaters, kiln linings, furnace doors, and similar apparatus. It is a high temperature insulator also used in the automotive and aerospace industries. It is listed as a suspected carcinogen.

The Refractory Ceramic Fibres Coalition (RCFC) alleged that it represented the major manufacturers of RCFC and that if ACGIH was allowed to publish the TLV, these manufacturers would suffer irreparable injury. Three RCF manufacturers constitute the membership of RCFC, and they include Thermal Ceramics Inc. of Augusta, Ga.; Unifrax Corp. of Niagara Falls, N.Y.; and Vesuvius U.S.A. Corp. of Buffalo, N.Y.

RCFC claimed that it had worked for years to lower exposure levels of RCF in the workplace and had proposed a tolerance of 0.5f/cc. RCFC reported that it had had a series of meetings with OSHA, and OSHA had indicated that it would support the industry position. However at the last minute, OSHA backed down. According to the complaint, the reason that OSHA backed down was because it learned that ACGIH was about to publish a RCF TLV of 0.2 f/cc. Further, the complaint alleged that Richard Fairfax, a high ranking OSHA official who was active in ACGIH, had been acting to undercut the industry's negotiations with OSHA and that OSHA was using the ACGIH TLV's as a way to avoid the rule making criteria under the OSH statute.

RCFC indicated that the effect of the TLV's was to establish a standard and that the RCF TLV of 0.2 f/cc was a standard that the industry could not meet. In papers filed the last week of December 2000, RCFC asked the Court to stop ACGIH from going forward. In response to the RCFC motion, the Court scheduled an emergency hearing early last month.

Within a week of receiving the RCFC papers, ACGIH filed a strong response with the Court. ACGIH denied that it was a standard making body and denied that Fairfax had anything to do with the decision to publish the RCF TLV. ACGIH explained that it was a private organization of industrial hygienists and occupational safety professionals. It members were employed by government agencies, academic institutions and private industry. Its members were all individuals and no members were government agencies. ACGIH receives no government grants.

The organization was established in 1938 to promote worker safety. Over the years it had developed an international reputation as a research organization and had developed a series of publications that were widely used by experts in occupational safety. ACGIH has published TLVs for various substances. Prior to publishing a TLV, a subcommittee is assigned the responsibility of developing all known information on the substance in question. The subcommittee then comes up with a recommendation together with a documentation of the major sources of information used to support the recommendation. The subcommittee recommendation is reviewed by the full TLV committee and if ratified, it is published on a notice of intended change list. The recommendation stays on the list for a least a year. During that time, interested parties have the opportunity to comment. After reviewing the comments, the subcommittee reconsiders its original recommendation. If it decides to go forward, the matter is resubmitted to the full committee. If the full committee ratifies the action of the subcommittee, the proposed TLV is sent to the ACGIH Board of Directors. If the Board ratifies the recommendation it is published.

ACGIH argued that the TLV's were not standards. As set forth in the TLV book published by ACGIH, the TLVs represent a statement that based on the evidence available, ACGIH has concluded the workers will not be exposed to unreasonable health hazards if exposure to any substance is limited to the level of the TLV. According to ACGIH, when Fairfax was given a high level of responsibility at OSHA in late 1997, he resigned from ACGIH committees and from the ACGIH Board of Directors and he had no input in the decision to publish the RCF TLV.

ACGIH's legal position was that it is a private scientific organization engaged in research on worker safety issues. Under the First Amendment of the U.S Constitution it is entitled to publish its opinions. ACGIH claimed that if the Court denied it the right to publish, every researcher who wanted to publish the results of his or her research would be faced with legal challenges.

The Court ruled in favor of ACGIH. The Court said that it did not appear the ACGIH was a quasi-government agency or that the TLVs were standards. The Court believed that ACGIH had the right to publish the RCF TLV and refused to grant the temporary restraining order requested by RCFC. The RCF TLV has been published on the ACGIH web site (www.acgih.org ) The case will now continue as RCFC 's complaint asks for damages. ACGIH contends that it is not liable for any damages in connection with the RCF TLV.

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NADCA's Revised ACR-2000 Standard To Be Unveiled This Month At Meeting 
by Glenn Fellman

A second public review draft of association's HVAC system cleaning standard will be unveiled when the National Air Duct Cleaners Association holds their 12th Annual Meeting & Exposition this month. After a year of refinement, the document comes forward freshly organized and substantially improved.

At their meeting one year ago, NADCA released the first public review edition of Assessment, Cleaning and Remediation of HVAC Systems for Hygiene. A lot has transpired since then. A new technical consultant was brought in to help the committee wade through the hundreds of comments to the first draft, reorganize the document and write new material. The standard has been retitled Assessment, Cleaning and Restoration of HVAC Systems - ACR 2000.

The original draft contained a complicated system of charts that were intended for use in classifying building type and the kinds of contaminants present within the HVAC system. That information was then transferred to additional charts that were intended to define the project scope, including such things as environmental engineering controls and cleaning methods. Commenter to the first draft said the chart system was too complex to understand and not practical for application in the workplace. The chart system was therefore removed entirely, and text was written for existing and new sections, in order to convey similar information in an easy to follow format.

The revision work called for taking a lot out of the standard - but it also resulted in many new sections and subparts being added to the document.

This article provides a section-by-section review of the new draft standard. Readers are encouraged to obtain copies of the public review draft and comment to NADCA.

Determining When to Clean

Perhaps the most significant new section to ACR 2000 is the section titled, "Determining the Need for HVAC System Cleaning." Here NADCA defines conditions that require cleaning. According to the standard, "HVAC systems should be cleaned when an HVAC cleanliness inspection indicates that the system is contaminated with a significant accumulation of particulate or microbiological growth. Likewise if the inspection shows that HVAC system performance is compromised due to contamination build up, cleaning is necessary."

The standard then provides a recommended inspection frequency for HVAC systems in different types of buildings, with details on the specific sections to be inspected.

NADCA has really broken new ground by answering the question: when is cleaning necessary? ACR 2000 truly goes where no cleaning guideline or standard has gone before by coving this controversial subject.

Planning The Project

If cleaning is deemed necessary, then the remainder of ACR 2000 is to be used to plan and execute the cleaning project. First users consult a section titled "Project Assessment." This section explains how to classify a building by usage type, how to characterize the contaminants within the HVAC system, and how to perform an environmental impact assessment.

Determining the building use classification is important, since the type of facility and its use to a large degree dictates the methods of cleaning and containment necessary. Likewise, assessing the types of contaminants present within the system is key to successful project planning. The environmental engineering controls required for projects involving routine dust contamination and significantly less strict than those required for projects involving gross microbial growth within the HVAC system. The environmental impact assessment required by the standard takes all of the information gathered during the building use classification and HVAC system contaminant assessment to ensure proper protection of the indoor environment during and after cleaning.

The next section of the standard, Environmental Engineering Controls, goes into specific detail on subjects like maintaining proper HVAC duct pressurization during cleaning, safe use of vacuum collection equipment, vacuum filtration requirements, and protection of building systems such as alarms and fire controls. A chapter of the Guideline appendix to ACR 2000 provides an excellent description of containment measures used to control debris within a workspace.

With the preliminary items covered in depth, the next section of ACR 2000 gets into the heart of the matter - HVAC System Cleaning. Portions of the system to be cleaned, specific methods of cleaning, cleaning tools and their minimum performance specifications are all covered. Additional sections follow that are specific to the cleaning of microbial contamination and the cleaning of fiberglass components. The standard takes a conservative approach. Porous materials that have been allowed to become wet are marked for removal. The use of chemical biocides is discussed, but cautiously recommended at best.

Next comes a new section - one on restoration. This section gets into specific requirements when cleaning water-damaged or fire-damaged HVAC systems. It also addresses situations were cleaning and restoration are not practical, and replacement of system components is warranted.

The last section of ACR 2000 builds on the meat and potatoes of the document's predecessors, NADCA Standard 01-1992, but defining methods for proving HVAC system cleanliness after cleaning is completed.

The first method of cleanliness verification is visual inspection. This is the most subjective of the three verification methods defined. However, it serves as a first line of verification and will often prove the only method necessary. If the consumer and contractor agree that the system appears free of dust and other contaminants, the project is said to have been completed successfully.

If visual inspection fails to produce conclusive results, the standard next prescribes a verification method called Surface Comparison Testing. Under this method, "the cleanliness of both non-porous and porous HVAC component surfaces may be evaluated by comparing visible characteristics of the surface before and after vacuuming with contact vacuum equipment." The method is simple, but effective. A section of the system is vacuumed with a hand vac. If it looks cleaner after vacuuming, then it wasn't clean to start with and the project may require more cleaning work.

For the final cleanliness verification method, NADCA falls back on the test originally defined 10 years ago - the NADCA Vacuum Test. This is a gravimetrical analysis of system components to scientifically measure the amount of debris present. What's new however, is the acceptable cleanliness threshold. The amount of debris considered acceptable has been reduced from 1.0 milligram per 100 square centimeters to 0.75 milligrams for the same surface area. To make the criteria even more stringent, the flow rate on the vacuum pump used to collect the sample has been increased by fifty percent - making the test even more difficult to pass.

The comment period for the new draft concludes on April 10. To obtain a copy of ACR 2000, contact NADCA at (202) 737-2926 or go to www.nadca.com.

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