CONSTRUCTION DUST – A STEALTH IRRITANT

Often overlooked, but frequently present, construction dust, which generally is identified as “calcite grains” or “gypsum grains,” can often be found as a factor in complaints concerning indoor air quality.  Remodeling or rebuilding and refinishing walls in an office or home will produce this fine grey/white and powdery particulate by sanding to smooth out irregularities in walls and ceilings. 

Construction dust is routinely detected in settled dust samples that are analyzed for composition.  When this material is found in relatively high percentage of the dust sample it becomes a suspect for certain symptoms.  This is of particular interest when symptoms reported are irritation to eyes, skin and respiratory system.  These symptoms are usually, at least initially attributed to the suspected presence of airborne fiberglass.  When fiberglass contamination is not detected in significant quantities, the next likely offender is construction dust. 

Construction dust contamination occurs due to improper containment of construction dust and debris during construction activities.  Often attempted isolation of construction activities consists of taping up a flimsy plastic sheet like the cheapest “paint drop cloths” sold in many home improvement stores.  If this is done at all, it has only minimal effect on containment of construction dust.  This material does usually get cleaned up after the construction project has been completed, but can remain in place for long periods of time in locations that are out of sight and seldom if ever cleaned. 

Other dust collecting locations include some light fixtures and pictures or other items that are hung on walls. 

Some of this construction dust that has become settled on surfaces can become airborne due to occupant activities and air movement from HVAC systems.

 Airborne construction dust as well as just general airborne dust can accumulate in fabric covered chairs and other porous materials, including carpets and partitions.  Sitting down in chairs with high dust content can routinely produce an invisible dust cloud, much of which is inhaled by the person occupying the chair and others in close proximity.

 HVAC systems are often run during construction activities, thereby contaminating the system and potentially exposing occupants in the entire area served by that system. 

One logical action to take to prevent or lessen construction dust contamination is simply to ensure that construction areas are properly contained so that the dust is not spread to other parts of the building.  A second action is if HVAC systems must be run during construction periods ensure the return vents are covered to prevent contaminated air from entering the airstream.  There must also be allowance for exhausting the air inside the containment area so that the construction area is not positively pressurized thereby forcing contaminated air to other parts of the building.  Of course the air must be exhausted to somewhere that it is not going to create a contamination problem there.

Once the construction has been completed and general cleanup has been done, it would be prudent to environmentally deep clean the area.  This consists of a thorough vacuuming of all surfaces (floors, walls and contents) using HEPA (High Efficiency Particulate Air) filtered vacuums.  Vacuuming should be followed by a wipe down of hard dust collecting surfaces (not electrical or fabric) with damp cloths.

When HVAC systems are found to be contaminated with construction dust the only option is to have them thoroughly cleaned to National Air Duct Cleaners Association (NADCA) standards including sanitizing the coils with an EPA registered product such as Oxine.  Environmental deep cleaning of the area served should follow immediately after the HVAC cleaning.

Breathe free!

Bake out vs. Flush out

In the last month or so, a client of mine told me that occupants of a property he manages had been complaining about apparent elevated levels of Volatile Organic Compounds (VOC) following some roof work.  I went to the site and spotted some less than optimum situations and recommended some remedies.  A week or two later I received a call from my client saying that his client had decided to do a bake out.  I was a bit surprised since it had been my understanding that this procedure had fallen into disuse in favor of the flush out.  This being the case, I decided to do a bit of research to better educate myself on the two techniques.  In the event that others might be interested, I decided to share what I found through my blog.

It was my understanding that a bake out was simply the use of heat to cause VOCs to off gas and that there was no particular use of ventilation.  A flush out as I understood it was introducing a large amount of outside air to a building for a period of time in order to increase the off gassing of VOCs and to disperse these gases via outside air.

I found these definitions to be fairly accurate, but I did find one definition of bake out that included increased ventilation to exhaust the emissions.  That additional item of the definition makes a big difference it the potential use of this methodology.

From the information I have been able to gather, there appear to be some problems with both techniques and a middle ground might be preferable.

Problems with the bake out are certainly obvious if significant outside air isn’t introduced, because without sufficient air change, VOCs are likely to become reabsorbed by porous and semi-porous materials.  Other problems concern the inability to uniformly heat up various building materials.  This might cause warping due to some connected materials expanding more quickly than others.  For example, concrete slabs heat up more slowly than many floor coverings, vinyl or wooden floors could warp as a result.  According to the Healthy House Institute – www.healthyhousinstitute.com – “Researchers also found that some chemicals were released into the air that aren’t released at normal room temperatures, and that the post-bake-out out gassing rates were hardly lower than the pre-bake-out emissions.  Bake-outs seem to have little effect on formaldehyde levels in a building, probably because formaldehyde-containing materials, such as particle board, are thick enough to have a substantial reservoir of formaldehyde in them.  It’s been suggested that part of the reduction in emissions that has been seen is due to the drying of concrete during a bake-out.  This results in a lower relative humidity indoors and lower out gassing rates.”

A flush out procedure can produce problems of its own, at least in hot, humid locales.  In moist climates, or even during rainy periods or those of particularly high humidity, the flush out could be problematic.  According to Environmental Observer, the newsletter of The Associated General Contractors of America, “Building startup procedures to meet LEED® credits include a credit flush-out of indoor containments using increased outdoor air either at the end of construction or during the initial occupancy period….  The amount of air needed to meet the flush-out requirements places a building at increased risk because of the moisture introduced with the increased outdoor air.  LEED®  requirements are that a minimum of 14,000 cubic feet per square foot of floor area is required for flush out.  This presents multiple problems: most HVAC systems are not designed to dehumidify that amount of outdoor air which, in a 100,000 square foot building, is 1,400 cubic feet of outside air.  Depending on the outside conditions at the time of the flush-out as much as 240,000 gallons of water can be added to a 100,000 square foot building.  This added moisture will be absorbed into building materials, finishes and furnishings, increasing the risk of mold growth.”

My conclusion after research on bake out vs. flush out, is that the use of either of these methods must involve a substantial degree of observation and common sense.  Often rote following of a rule or applying a specific procedure to a wide variety of situations can result in unforeseen problems. 

I seriously doubt that using a bake out without also increasing ventilation would be particularly effective and could present problems with materials inside the building.  At times combining an increase in temperature with the flush out might make sense, but perhaps not pushing the temperature up into the 90’s. 

In terms of the flush out, the outdoor conditions must be taken into consideration.  From an indoor air quality viewpoint, I tend to favor substantial outside air for dilution of contaminants, but I realize that in any endeavor analysis of costs and benefits are necessary.  Often with LEED® buildings and construction schedules getting behind, there is a rush to get the building occupied.  The reduced flush out along with an overall increase of outside air provided via the HVAC system with the building occupied could be a solution in a lot of cases, but outdoor conditions still need to be taken into consideration especially in terms of humidity.  In any case, it seems to me that studies need to be done for the purpose of developing proper flush out procedures based on a variety of outdoor temperatures and humidity.  The result of such studies could result in guidelines for proper procedures to achieve acceptable indoor air quality by application of flush out/bake out based upon outdoor temperatures and humidity at the time these activities are undertaken.

Legal Department
Associated General Contractors of America

2300 Wilson Boulevard, Suite 400
Arlington, VA 22201
USA

http://www.agc.org

Air Movement Systems - To Clean or Not to Clean…

To clean or not to clean!  That is the not question?  With regard to cleaning or not cleaning air movement systems, it should not be a question at all. The real question should be “What technique is being used to clean the air movement system?” Ads that propose to clean ducts of an entire house for “$39.95” or “$69.95” or “$99.95” or some such low price, signal abuse to the degree that it could reasonably be called fraud.  The fact is, to properly clean ventilation systems, including air ducts, requires a certain amount of time, labor, expertise and equipment.  So proper cleaning can be relatively costly, but doing it right is absolutely crucial!

Just because you have filtration, even good filtration on HVAC (Heating, Ventilation and Air Conditioning) systems does not prevent the interior from accumulating particulate matter (dust/debris).  Even high quality filters will allow some small particulate matter through including particulate from the filters themselves.  This can account for substantial accumulation after a number of years.  Consider problems like air bypassing filters, missing or deteriorated seals or gaskets, breaks, disconnections or other leaks inside ducts.  These and other conditions result in dust accumulating inside ventilation systems.  In cooling mode, air flowing through coils causes condensation.  This water must be channeled properly or microbial growth inside the HVAC system can result.  Improper design or operation of the condensate water drain system can cause leaks or flooding inside.   Accumulated organic matter becomes a food source for molds and bacteria.

Dust is not just dirt.  Dust is an accumulation of a wide variety of materials including potentially irritating, toxic or allergenic particulate.  Usually the major component of dust inside a building is flaked off skin, or dander.  This is organic material that with added moisture is food for mold and other microbes.

Dirty cooling coils that become clogged with particulate matter will cause air to rush at greater speed in those portions that are not clogged.  This results in water droplets being blown off the coil, combining with organic matter to produce mold growth in the air handler beyond the coil and potentially in supply ducts.

Fiberglass insulation inside air handlers and ducts will eventually become torn or deteriorated, resulting in fibers collecting in the air pathway and eventually blowing out into the occupied space, potentially affecting occupants.

Failure to clean HVAC systems correctly and completely has stoked the fire of controversy.  It was because of abuses in this field that the National Air Duct Cleaners Association (NADCA) was formed and guidelines established for proper cleaning.

NADCA has stated: “Research by the U.S. EPA (Environmental Protection Agency) has demonstrated that HVAC system cleaning may allow systems to run more efficiently by removing debris from sensitive mechanical components.  Clean, efficient systems are less likely to break down, have a longer life span, and generally operate more efficiently than dirty systems.”

The EPA writes, “If not properly installed, maintained and operated, these components (heating, ventilating and air-conditioning components) may become contaminated with particulates of dust, pollen, or other debris… Failure to clean a component of a contaminated system can result in re-contamination of the entire system, thus negating any potential benefits.”

It seems clear that cleaning of air movement systems is a correct action if done properly.  There are many ways, unfortunately, to clean these systems poorly. 

How about inserting the hose of a shop vacuum into a ventilation supply register and turning the vacuum on?  This is the method used by what are referred to in the industry as "blow and go” duct cleaners.  Companies that advertise cleaning of entire systems for $69.95 or a similar price, generally use this method.  Common sense would dictate doubt in the effectiveness of such a method. 

Fogging the interior of the ducts with a biocide containing encapsulating material, either in conjunction with or instead of the shop vacuum method is another technique I would label improper.   According to the EPA, biocides can have a worse effect on occupants than microbes.  These encapsulants do not cover the interior thoroughly, but tend to puddle at the bottom. “Coating the dirt” is never a good idea and doing it poorly makes matters worse. In some cases, such as when significant fungal or bacterial contamination has been established as present or was suspected as being present inside ventilation ducts, fogging with an EPA registered sanitizer (not an encapsulant) after source removal could be appropriate.

Sucking dirt and debris out of the ducts using a power vacuum or a negative-air machine that collects the material is another practice sometimes employed. Equipment is hooked up to the ducts to suck out the offending material. There may be some limited applications for this method, but potential damage to ducts is possible due to the suction created.  In most cases, a large portion of the dirt inside is caked on and must be agitated to be effectively removed.  If not removed, this material can later enter the airstream due to any of a variety of disturbances.

 Some duct configurations might be suitably cleaned using the above mentioned equipment along with compressed air to help loosen and direct the debris.  A “skipper” or “whip” or a rotating brush can be used to loosen caked on dirt.  Variations of this equipment can be effective, especially for small, inaccessible metal ducts that are in good condition.  Properly sized equipment is essential in such operations. 

None of the above methods are fully effective in cleaning dampers, turning vanes or duct-joint seams. 

To clean ducts completely, you often have to get dirty!  Hand brushing and HEPA vacuuming at least part of the duct interiors is needed to clean most duct systems fully.  Access ports are cut into ducts to permit a serviceman to brush and vacuum interior surfaces including turning vanes, seams, etc.  Joints or access ports must be properly closed and sealed after cleaning.

Pressure washing coils plus repair or replacement of fiberglass liner in air handlers and ducts plus sanitizing the coils using an EPA registered sanitizer should be done along with duct branch cleaning.  Replacing deteriorated or microbially contaminated insulation with a non-fiberglass liner is also recommended.

The bottom line on cleaning of HVAC systems is that often a combination of methods might be needed.  The techniques should be determined by what is suitable to the particular system or situation as judged by a properly trained and experienced technician.  Just because you know how to sweep a floor doesn’t mean you can now claim to be a duct-cleaning professional.  This, I submit, is the basis of the controversy.

How often ventilation systems should be cleaned depends largely on the type of environment in which the system exists, the efficiency of seals, gaskets and filtration plus the quality of maintenance.  Cleaning air handlers, particularly coils should be done once a year.  Ducts should be cleaned about every five to ten years.  A specific time line for cleaning any part of HVAC systems should not supercede visual inspections that can better determine the necessity for cleaning.  Anyone who has doubts if a system needs cleaning should simply contact NADCA for guidelines and either look for himself or get a NADCA Certified HVAC Inspector to look for you.

I see no valid reason to question the need for cleaning ventilation systems. Underpinning this dispute is the lack of knowledge of methods for proper and complete cleaning of the various duct materials and configurations.  There is no doubt in my mind that dirty HVAC systems will lower the quality of indoor air.  It follows that proper and complete cleaning of dirty HVAC systems will improve indoor air quality of the space served.  I believe that this conclusion works logically and empirically.  Readers are, therefore, invited to test the supposition on their own and perhaps put an end to this dispute once and for all.

Annual Inspections of HVAC Systems Law

The Law Concerning HVAC System Operation, Inspections and Maintenance – Clarified (At least to a degree)

Below is the wording of the Title 8 law concerning yearly inspections of HVAC systems.  This is a law that has seldom, if ever, been enforced.  I am calling it to your attention due to the current state of the California economy and with the state being strapped for cash.  I’m sure no one would be surprised to find that various state departments might be encouraged to increase enforcement of some laws with at least an underlying purpose of increasing revenue via fines.  Title 8 certainly falls in this potentially revenue-lucrative category.  Very few organizations that I am aware of comply with this law and thus are easy prey for California State inspections and fines.

Interspersed with the text of the law below are my comments that to a degree explain what it takes to comply with it.  This obviously is not coming from a legal perspective, but from what I know by delivering inspections and testing in order for organizations to comply with it.

My comments are in this font.

TITLE 8, Sub Chapter 7.

§5142 Mechanically Driven Heating, Ventilating and Air Conditioning (HVAC) Systems to Provide Minimum

Building Ventilation.

(a) Operation:

(1) The HVAC system shall be maintained and operated to provide at least the quantity of outdoor air required by the State Building Standards Code, Title 24, Part 2, California Administrative Code, in effect at the time the building permit was issued.  For office buildings the volume of outside air is 15 cubic feet per minute (CFM) per occupant or 0.15 CFM per square foot of space served.  Older buildings might be “grandfathered in” at as little as 5 CFM per occupant.

(2) The HVAC system shall be operated continuously during working hours except:  The supply fan must run continuously during working hours in order to supply outside air even when there is no temperature demand.

(A) during scheduled maintenance and emergency repairs;

(B) during periods not exceeding a total of 90 hours per calendar year when a servicing electric utility by contractual arrangement requests its customers to decrease electrical power demand, or;

(C) during periods for which the employer can demonstrate that the quantity of outdoor air supplied by nonmechanical (operable windows) means meets the outdoor air supply rate required by (a) (1) of this Section. The employer must have available a record of calculations and/or measurements substantiating that the required outdoor air supply rate is satisfied by infiltration and/or by a non-mechanical-driven outdoor air supply system.  Along with records that the fan runs continuously, a written report showing the volume of outside air provided is needed.

(b) Inspection and Maintenance:

(1) The HVAC system shall be inspected at least annually, and problems found during these inspections shall be corrected within a reasonable time. A written report showing problems with recommended actions to correct would be needed along with evidence that correction has taken place.

(2) Inspections and maintenance of the HVAC system shall be documented in writing. The employer shall record the name of the individual(s) inspecting and/or maintaining the system, the date of the inspection and/or maintenance, and the specific findings and actions taken. The employer shall ensure that such records are retained for at least five years.  Same as the above statement and of course the records retained for five years.

(3) The employer shall make all records required by this section available for examination and copying, within 48 hours of a request, to any authorized representative of the Division* (as defined in Section 3207), to any employee of

the employer affected by this section, and to any designated representative of said employee of the employer affected by this section.  Besides state officials, employees can request the records and if now forthcoming can report this to state officials.

For a reasonable price Machado Environmental, along with many reputable environmental companies, can provide an inspection service that enables easy compliance  with the annual inspection and maintenance portions of this law [§5142, paragraphs (b)(1) and (b)(2)].  For more information, contact Machado Environmental at 1 (800) 358-3828.

SMOKE GETS IN YOUR...NOSE!

Over the years tobacco smoking and the aftermath of this activity have become favorite subjects of concern for a wide variety of media, and individuals as well.  Reformed smokers tend to be the biggest complainers.  I, myself, smoked non-filtered Lucky Strike or Pall Mall while I was in the Marine Corps.  Filtered cigarettes are frowned upon because they cannot be “field stripped.”   You field strip a cigarette butt by tearing the paper apart, removing the tobacco and disbursing to the wind and then balling up the paper and discarding it.  This way there is very little trace that the enemy can detect. 

I managed to quit some 25 years ago at a time when you could smoke essentially anywhere.  This was a number of years prior to my indoor air quality career and in a relatively high pressure job.  There were times when I might have a cigarette burning in an ashtray, one perched on the side of my desk and I’m reaching in my breast pocket to light up another.  Those were the days when a habit was really a habit.  I’m quite thankful that I managed to quit.

Fast forward 20-some years and the restrictions on smoking have reduced the number of smokers and therefore much of the aftermath brought-on by this activity.  My purpose in this article is to give some guidance for removing the odor that can linger long after any smoking in a dwelling has stopped.

These are the steps I would take in order to remove long-standing smoke odors from a house.

1)      If weather permits, open lots of windows.  Fresh air is a good de-odorizer.  The greater amount of fresh air provided, the greater the effect on the odorous area.

2)      Make coffee and leave the coffee can open.  People will often brew coffee to cover up unpleasant odors, but cover-up is not all this does. Coffee beans neutralize odors, so maybe open several cans. 

3)      Launder or dry clean any fabric materials that can be.  It might require more than once to remove all of the odor.

4)      If carpets have padding and the carpets are serviceable, remove and discard the padding before attempting to clean the carpets.  Sprinkle banking soda over carpets and fabric covered furniture, wait a few hours and then vacuum thoroughly.  Baking soda is relatively inexpensive so use enough to have an effect.  Some fabrics can react unfavorably with baking soda, so you might need to test that before proceeding.  Shampooing the carpets after vacuuming using a hot water deep extraction method can be done to help remove more of the odor.

5)      Walls, ceilings and hard floors may have to be washed.  Especially if the previous occupant was a heavy smoker, the surfaces could be yellowed due to a tar build-up.  Washing these surfaces with a cleaning solution including vinegar will not only reduce the smoke odor, it will likely make the room look brighter. The acid in vinegar cuts through the tar and helps to neutralize the smoke odor.  Change the cleaning solution often as it will lose its effectiveness.  Using vinegar might make the area smell like a salad for a few days, but that odor will dissipate much sooner than the tobacco smell.  Light bulbs should be included in this cleaning as they tend to attract smoke and then release these odors as they heat up when in use.

6)      You might want to repaint walls and/or ceilings, but if so do it after the clean-up.  It is seldom a good idea to pain over any contamination.

7)      If you have a forced-air heating, ventilating and air conditioning (HVAC) system, it should be thoroughly cleaned to National Air Duct Cleaning Association (NADCA) standards including sanitizing the coils with an EPA registered product.  Deodorizing the ducts should also be done.

8)      Ozone generators, or ozone machines are often used professionally after fires to rid the area of the smoke and burnt odor and at high levels, have been proven to reduce or eliminate odors of all types, including residual tobacco smoke odors.  At high levels, though, ozone is harmful to the lungs, so if this method of odor removal is used, the manufacturers' safety guidelines must be strictly followed. Some older models of air purifiers also contained ozone generators, some of which produce ozone at relatively high levels. Set the air purifier, turn on the fan of the HVAC system and vacate the house.  Come back in 24 hours, turn off the air purifier, keep the HVAC fan running, open as many windows as possible and vacate the house for another 24 hours.  That should be enough time to dissipate the harmful levels of ozone.

9)      Lastly, if there are still lingering odors, equip your HVAC system with carbon treated filters, which will help to absorb odors on a continuing basis.  Of course, it might be necessary to repeat some of the above actions to neutralize smoke odors completely. 

Let’s hope you do not have to go through all of the above steps in order to create a pleasant indoor air environment, but know that in general, this odor situation can be eliminated with some patience, effort and a bit of knowledge.

IT MIGHT NOT BE MOLD!

Family members complain about air quality in the home.  They cough or sneeze or have irritated eyes or have headaches or rashes or a variety of other symptoms.  And it happens only when they are in the house.  Looks like you have a mold problem!  Well, maybe not. 

The awareness of mold and mold related symptoms in the indoor environment over about the last two decades has resulted in mold becoming the evident and easy target to relieve these symptoms.  Often after time consuming testing for mold growth and/or airborne mold spores, you often come up empty.  Professionals who do this testing do not come cheap, so the expense can easily induce “sticker shock.”

In order to combat this common scenario, Machado Environmental has developed the inexpensive Indoor Air Quality Basic Health Check.  Delivered by our Indoor Air Quality Professionals, indications of mold are always checked for by an expert eye, but there are a variety of potential air quality issues that we test for with our program.  In relatively short order we test for a number of contaminants that can be found in virtually any home environment.  Included in the Basic Health Check is testing for temperature, relative humidity, carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2) level, total volatile organic compounds (TVOC), Hydrogen sulfide (H2S), combustible gases, airborne particulate, dust reservoirs in furniture and carpeting, and volume of outside air if provided by the ventilation system.  We also perform a hygienic inspection of the ventilation system serving the area plus checking the thermostat setting.  Based on the observations and testing data, we provide a certificate indicating that all parameters are within acceptable limits based on accepted indoor air quality standards.  The certificate is colorful and suitable for framing, if you like.  If there are items outside of these standards, we make recommendations to remedy those factors.  This includes any non-optimum situations observed with the HVAC system.

We perform the Indoor Air Quality Basic Health Check for a single location including the HVAC system that serves the area for a very reasonable fee.  The entire activity is expected to require about an hour.  Additional locations tested during the same site visit would be discounted below the one location price.  If it makes sense or is requested to perform additional testing, such as samples for microbial growth in the ventilation system, there would be an additional charge.  We would only take additional tests or samples, however, after clearing it with you, our client.

You are invited to call Machado Environmental for pricing and to schedule your Indoor Air Quality Basic Health Check.

Stephen Huff

Director, Indoor Air Quality Investigations

Stephen Huff is a Certified Microbial Consultant (CMC) and Certified Indoor Environmental Consultant (CIEC).  He is the author of Breathe Free or Die, The Layman’s Guide to MOLD and Other Indoor Air Quality Problem.

Message to readers

I will be posting articles covering a wide variety of subjects about or related to indoor air quality.  Many of these articles will challenge or be somewhat counter to conventional wisdom.  Especially for this reason, I encourage comments and questions.  I don't claim to be the final word on the subjects about which I write.  I am open to be educated, either by experts in the field or those who have personal experience dealing with subjects concerned.

Thank you