What “IS” a Mold Inspection?

July 14, 2016

I once again raise this question because I’ve been called in to provide yet another second opinion of a mold inspection that consisted of nothing more than the collection of a few air samples for mold spores.  I assure you that a correct mold assessment in accordance with the only industry standard of practice does not involve the random sampling of mold.  The only industry standard of practice is the ASTM D-7338 Assessment of Fungal Growth in Buildings.

The question of just what is a mold assessment is a frustrating and surprisingly hard question for many industry professionals to answer.  That’s right; many mold professionals just don’t know their own industry well enough to know the prevailing standard of practice.  When I’m asked to provide a second opinion on a mold inspection, I always want to talk with the original mold assessors.  Given the chance, I will always take the opportunity to try to raise the awareness of the original mold assessor and inform them of the ASTM D-7338 and the process of providing a valuable mold assessment and report.  I feel that this is best for our industry and for the consumer.

So just what is it that many mold assessors believe is a mold inspection?  Many believe that a mold assessment is simply testing for mold.  There is plenty of guidance on the value of mold sampling but if the ill-informed mold assessor isn’t aware of the industry standard of practice, the ASTM D-7338, there is little chance that they will be aware of the very public opinion of mold sampling.

Let’s just review the industry position on mold sampling.  Ten years ago, the ACGIH concluded that air testing provided a “snap shot” of conditions at the exact time and place of the sampling, but nothing more.   The Center for Disease Control, CDC’s current position is that air sampling for mold is nothing more than a snap shot and that such a snap shot is not reliable, representative or worth the cost. The CDC states very clearly that “Any claim based solely on air sampling results is inherently suspect.”  The CDC goes on to state that “There is no reason to respond to questionable testing by conducting more of it.  I believe that is a very clear position from a reputable source.

What does the laboratory say about the interpretation of the collected mold samples?

  •        The client is solely responsible for the use and interpretation
  •        Note: Interpretation is left to the company and/or persons who conducted the field work.
  •        The “Lab” shall have no liability to the client or the client’s customer with respect to decisions or recommendations made, actions taken or courses of conduct implemented by either the client or the client’s customer as a result of or based upon the Test Results.

The mold assessor that collected the mold samples is the laboratory’s client not the property owner.  That is something that the mold sampler seems to not understand.

Let’s look a bit further. When the following governmental and industry organizations were asked if mold testing is necessary, this is what they had to say.

  •        American Industrial Hygiene Association, AIHA There are no standards for “acceptable” levels of mold in the indoor environment. If you know you have a mold problem, it is more important to spend time and resources solving the moisture problem and getting rid of the mold than to spend it on sampling.
  •        US Environmental Protection Agency, EPA If you know you have a mold problem, it is more important to spend time and resources solving the moisture problem and getting rid of the mold than to spend it on sampling. If visible mold growth is present, sampling is unnecessary.  Since no EPA or other federal limits have been set for mold or mold spores, sampling cannot be used to check a building’s compliance with federal mold standards.
  •        Occupational Health and Safety Administration, OSHA In most cases, if visible mold growth is present, sampling is unnecessary. Your first step should be to inspect for any evidence of water damage and visible mold growth.
  •        U.S. Department of Labor There are no standards for acceptable levels of mold in buildings, and the lack of a definitive correlation between exposure levels and health effects makes interpreting the data difficult, if not impossible.
  •        Center for Disease Control, CDC There are no accepted standards for mold sampling in indoor environments or for analyzing and interpreting the data in terms of human health.  Molds are ubiquitous in the environment, and can be found almost anywhere samples are taken.  It is not known, however, what quantity of mold is acceptable in indoor environments with respect to health.  CDC does not recommend routine sampling for molds. Generally, it is not necessary to identify the species of mold growing in a building.  Measurements of mold in air are not reliable or representative.  If mold is seen or smelled, there is a potential health risk; therefore, no matter what type of mold is present, you should arrange for its removal.
  •        The Florida Department of Health, The Florida Department of Health does not recommend mold testing or sampling to see if you have a mold problem, or to see what kind of mold might be growing.
  •        NYC Guidelines on Assessment and Remediation of Fungi in Indoor Environments, The Department of Health, DOH, should continue to emphasize in its public education materials that sampling for airborne mold is unlikely to provide reliable information for decision-making in damp or moldy buildings.

So, should you sample for mold? No, never for the purpose of mold investigation.  Why? There are too many variables impacting the results and the sample size is too small for air testing for mold to be reliable.  The type of mold will not change the necessary mold remediation.  The genus of mold is just not relevant or necessary unless you are trying to frighten a client into believing that they have “Toxic” mold.  Mold spore trap air samples do not have the ability to establish the presence of any mycotoxins.  Air sampling’s lack of utility in determining the level of mold found in indoor air may be a surprise to some, given the frequent references to these tests and mold litigation.  Unfortunately, those that reference mold testing in mold litigation are never directly involved in mold litigation or they would know what the reality is, mold sampling to the genus level is worthless in court.

Mold assessors should bear in mind that samples provide information about a site as it existed at the time tested.  However, the findings may not represent conditions at a time in the past or future, even the relatively recent past or near future. Changes in the kinds, concentrations, and proportions of biological agents in the air can be rapid and substantial.  Bioaerosols: Assessment and Control, Section 2.4.2.2.

ASTM D7338 Standard Guide for Assessment of Fungal Growth in Buildings 7.1 The most important requirement of an assessment for fungal growth is an on-site inspection of the subject building. It is very important to remember that the ASTM D-7338 is the only recognized standard for mold assessment.  According to the ASTM D-7338 the parts of a mold assessment include:

  •        the collection of background information,
  •        the formulation of a hypothesis or hypotheses,
  •        on-site inspection including moisture dynamics,
  •        an evaluation of the HVAC system,
  •        hypothesis testing,
  •        site documentation and written report.

The scope of work defines the problem and, just as importantly, which part of the basic assessment and which of the procedures are to be performed.   The scope of work will define the inspection boundaries.  The ASTM D-7338 clearly states that “Within the inspection boundary, all surfaces should be inspected to the extent feasible, including

  •        above suspended ceilings and
  •        inside pipe chases,
  •        attics, and
  •        crawlspaces.

The exterior of the building and adjacent grounds should also be inspected for moisture intrusion sites and air leaks.”

The mold inspector that only samples for mold and provides nothing more than a laboratory report will attempt to exclude virtually all areas of a building from his responsibility.  Below is an excerpt from a peer reviewed mold inspection report “Disclaimer”.  It is a remarkable example of how some mold inspectors attempt to alleviate themselves form the responsibility of the very job that they were hired to perform.

DISCLAIMER

Certain areas are considered inaccessible and impractical to inspect including, but not limited to,

the interiors of walls and inaccessible areas below; areas beneath wood floors over concrete; areas concealed by floor coverings; and areas to which there is no access without defacing or tearing out lumber, masonry, roofing or finished workmanship; structures; portions of the attic concealed or made inaccessible by insulation, belongings, equipment or ducting; portions of the attic or roof cavity concealed due to inadequate crawl space; areas of the attic or crawl space made inaccessible due to construction; interiors of enclosed boxed eaves; portions of the sub area concealed or made inaccessible by ducting or insulation; enclosed bay windows; portions of the interior made inaccessible by furnishings; areas where locks prevented access; areas concealed by appliances; areas concealed by stored materials; and areas concealed by heavy vegetation.

There is no economically practical method to make these areas accessible. However, they may be subject to attack by microbial organisms. No opinion is rendered concerning the conditions in these aforementioned or other inaccessible areas. Furthermore, mold grows. As such, the inspection and report produced by Mold Assessor is not a guarantee that mold does not exist.

As a courtesy Mold Assessor may point out conditions that contribute to mold growth but such comments are not part of the bargained for report, protocol, or supplemental information. The protocol is not intended to be either exhaustive or inclusive of all pertinent requirements, methods or procedures that might be appropriate on a particular mold remediation project.

Anyone using this document should understand the limitations with its use, and rely on his or her own independent judgment, or as appropriate, seek the advice of competent professionals in determining the exercise of reasonable care in any given situation.

This type of disclaimer is an example of how some mold inspectors are intent on limiting their area of responsibility.  What exactly are property owners that hire this mold inspector paying for?  What exactly is the value provided by the mold assessor?  Most importantly, why the need to limit the area of responsibility in direct contradiction to the ASTM D-7338?  The answer is that this mold assessor, like many, had no idea that the ASTM D-7338 even existed. This mold assessor, like many, felt that the simple collection of air samples for mold was a mold inspection in direct contradiction to the government and industry positions sited above.

As with any industry the mold industry has a standard of practice that must be followed to provide a property owner with necessary and relevant information regarding any possible mold issue within their property.  Mold sampling will never have the ability to provide any of that necessary and relevant information

A mold inspection in accordance with the ASTM D-7338 will provide the property owner with a wealth of necessary and relevant information.

The ASTM D-7338 states in Section 7.5.3 Identification of Current Water Damage and Suspect Fungal Growth

  •        All surfaces within the inspection boundary should be systematically evaluated for indicators of moisture damage and fungal growth.

Exposed surfaces (including building materials, furnishings, and contents) should be examined for past and ongoing damage including:

(1)  suspect fungal growth,

(2)  standing water

(3)  water stains,

(4)  dampness to touch, and

(5)  blistering, warping, de-lamination, or other deterioration.

The ASTM D-7338 states in Section 7.5.4 Identification of Potentials for Fungal Growth

The inspection should identify moisture sources and moisture pathways, including:

(1)  sites where condensation may occur,

(2)  equipment or activities which may release water,

(3)  pathways for water movement and

(4)  areas where leakage is likely.

–  Staining patterns are often useful in identifying moisture sources.

The ASTM D-7338 states in Section 7.5.5 Presence of Odors

Detection of musty odors should always be noted.

(1)  Sources of such odors should be located.

(2)  If the source is not apparent, intrusive investigation may be required.

The ASTM D-7338 states in Section 7.5.6 Classification of Inspection Observations

Classify each distinct area or area of interest within the inspection boundary as one of the following categories:

(1)  no apparent fungal growth and no apparent water damage;

(2)  water damage having no visually suspect or confirmed fungal growth,

(3)  visually suspect or confirmed fungal growth having no apparent water damage, &

(4)  water damage having visually suspect or confirmed fungal growth.

The ASTM D-7338 states in Section 7.5.8 HVAC Inspection, if applicable per the scope of work

The interiors of HVAC equipment in contact with ventilation air should be inspected for indicators of excessive moisture or suspect fungal growth.

Such areas may include intake and return plenums, filters, coils, condensate pans, fans, housing insulation, and supply ducts immediately downstream from the coils.

The ASTM D-7338 states in Section 7.6.1 Site Map—A site/floor plan should be prepared showing each inspection classification, as determined in 7.5.6.

The plan should be sufficiently detailed to allow each area of interest to the assessment to be unambiguously located.

The ASTM D-7338 states in Section 7.6.2 Documentation of Suspect Fungal Growth—Wherever suspect or confirmed fungal growth is identified during the inspection, documentation should include:

(1)  extent (for example, approximate square footage of suspect growth),

(2) severity (for example, relative darkness or continuity of stain), growth pattern (for example, light versus heavy growth and spotty versus continuous growth), and

(3)  clues to apparent cause (for example, exterior wall, condensation near a HVAC vent, associated with water staining).

The ASTM D-7338 states in Section 7.6.3 Documentation of Moisture Damage—In addition to documenting the location of moisture damage, as above, further documentation should include:

(1)  apparent sources of leaks and other moisture sources, and

(2)  apparent timing and duration (for example, whether the moisture has been resolved, active (currently wet) or the moisture source is likely to reoccur

The ASTM D-7338 states in Section 7.6.4 Visual Documentation—Photographs or videotapes are often helpful in documenting building conditions. Captions should note location, timing, and context.

The ASTM D-7338 states in Section 7.6.5 Additional Detail—Start and stop time, temperature, humidity, occupancy, condition, and housekeeping of the property.

With a clearly written standard of practice for mold assessment, it’s truly hard to believe that there are so many mold assessors that provide a client little more than a few air samples for mold and call it a mold inspection.  Worse yet is when these mold inspectors call the simple collection of air samples for mold air quality samples.  Both are perfect examples of over selling and under delivering.

More importantly, I would stress that a mold assessment is NOT the collection of mold samples or testing for mold.  It may include the collection of mold samples but the collection of mold samples is NOT, on its own, a mold assessment.

If you hire a licensed mold assessor you should receive a written report in accordance with the ASTM D-7338 signed by the licensed mold assessor that performed the assessment.  Not by someone in another location that never visited your home or office.  When you hire a licensed mold assessor you should receive the written report signed by the licensed mold assessor that performed the assessment and never be required to pay an additional fee for a written report.

That’s ridicules, what are you paying for if you aren’t receiving a written mold assessment report from your licensed assessor.

So what should the written mold assessment report include?

As the ASTM D-7338 clearly states.  A detailed evaluation of data obtained from a building history and inspection to formulate an initial hypothesis about the

  •        origin,
  •        identity, location,
  •        and extent of amplification of mold growth

The written report can then be provided to licensed mold remediators that can then provide you with a written estimate for the remediation.

Finally, I close with questions you should ask your mold assessor before you hire them.

o    (Tip: You’re looking for conflicts of interest here. If they also perform remediation, they have a vested interest in finding mold to clean up.)

  •        Do you have references from clients within the past year that I can call to ask how the inspection went?

o   (Tip: Be cautious of anyone new to the business and doesn’t have references.)

  •        Do you perform mold remediation?

Please, as a take away, always ask if your mold assessor is Licensed and aware of the ASTM D-7338

 

Thank You

 

John P. Lapotaire, CIEC

Indoor Air Quality Solutions, IAQS

www.FloridaIAQ.com

Indoor Air Quality Association, IAQA President

www.IAQA.org

 

 

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Posted by John P. Lapotaire, CIEC

“Spray Polyurethane Foam Insulation Build it Tight and Ventilate it Right” Part III

June 14, 2014

ImageIt’s time to reduce your carbon footprint and a great way to begin the process is to re-insulate your home.  You’ve been told that it’s a simple process of adding new spray polyurethane foam insulation in the attic.  You’ve been told that you can save up to 20% on your next energy bill.  You’ve also been told that you’re currently losing as much as 40% of your homes energy efficiency due to air infiltration.

Spray foam offers a solution: it performs as both insulation and an air sealant, or air barrier, closing those nooks and crannies that let air escape and add dollars to monthly energy bills. You’ve double checked what your SPF salesman has told you about the energy savings and found that the U.S. Environmental Protection Agency’s (EPA) Energy Star program estimates that by adding insulation and sealing air leaks you can save up to 20% on your monthly energy bills.

You’ve also found that the U.S. Department of Energy estimates that 56% of the energy used in a home goes to heating and cooling. Your home’s heating, ventilating, and air conditioning (HVAC) system has a big effect on your utility bills and your energy consumption because it has to work hard to keep up with all that air leakage.

You’ve done your homework and you’ve decided to move forward with your purchase and application of spray polyurethane foam insulation in your home’s attic.  You’re excited about increasing your “R” value and saving those energy bucks but still just a bit concerned about all those potential indoor air quality IAQ issues that you have been reading about while researching the energy savings of SPF.

Spray foam insulation can help reduce the workload on your HVAC system thanks to its high R-value and effectiveness. In fact, with spray foam, HVAC sizing can be reduced as much as 35% without the loss of efficiency and comfort.

With some luck you’ve read my previous articles and have asked some very critical questions prior to your decision.  Remember, there are differences between spray polyurethane foam insulation and blown or batt insulation that go well beyond the R value and energy savings.

All insulation products aren’t created equally and some insulation products provide much more than just R Value.  When you install spray polyurethane foam SPF insulation, you change the way your home performs.  You’re reducing your homes air leakage or air infiltration.  Great stuff right?  Well, yes and no.  Yes for energy efficiency – less is more analogy is a good thing; however, when it comes to your indoor air quality, IAQ, less is definitely not more and absolutely not better.

Your home’s air leakage or air infiltration rate is the source of the home’s air change rate ACH.  When you seal up your home you may also be substantially reducing your home’s ACH.  When you insulate with SPF you’re not just improving your home’s R-value, you’re changing the way your home achieves the ACH necessary to maintain good indoor air quality.

Today, we have very specific guidance documents that help both the consumer and the applicator better understand the difference between a traditionally ventilated attic and a SPF unvented attic.

Guidance on Best Practices for the Installation of Spray Polyurethane Foam established by the Spray Foam Coalition of the American Chemistry Council, ACC, Center for the Polyurethanes Industry states that the contractor and the homeowner should be aware that retrofitting an existing attic by employing an unvented attic assembly technique can result in the existing HVAC system becoming “oversized” in relation to the new demand.

This situation is of special concern in the southern and coastal climate zones where the HVAC also serves to reduce or otherwise manage moisture levels of buildings in order to improve comfort and prevent moisture related problems, such as mold and mildew. If an existing HVAC becomes “oversized” due to the increased thermal efficiency of the unvented attic assembly, the HVAC system may begin to short cycle, or to quickly turn on and off, as it works to manage temperature. This short cycling of the HVAC system may have negative impacts on the comfort and efficiency of the building and possibly on the lifespan of the system.

The guidance document recommends that the application contractor involve an HVAC consultant to adapt the system to the new, more efficient building envelope associated with the spray foam retrofit.

By far, the majority of the complaints I respond to are a direct result of inadequate ventilation and no method or design consideration for the now semi-conditioned attic.

The Spray Polyurethane Foam Alliance, SPFA Builder’s Reference Handbook, list the HVAC and Ventilation as one of their initial Design Considerations.

The SPFA Builder’s Reference Handbook recommends an Initial Evaluation “Test In” and a Final Evaluation “Test Out”
Initial Evaluation (Test-In)

The Initial Evaluation (Test-In) is a complete evaluation of the existing home before the installation of the SPF insulation.

Items to address and checked during the Test In can include:
•  Air Leakage Testing, to establish the air infiltration rate
•  Existing Attic Insulation (type location and recommended method of removal)
•  Inspection of Related Systems (e.g. HVAC, kitchen, and bathroom exhaust ventilation)
•  Combustion Appliances (reduced ACH and make-up air may be an issue as well as ventilation)
•  Energy Savings Estimate by independent trained professionals (BPI and RESNET)

The Test In air leakage testing is performed using a blower door to evaluate the home’s air leakage and natural ventilation before SPF application.  This is then used as a baseline for quality checks and energy savings estimates.  This test for existing homes should be performed before and after SPF installation.

This initial air leakage or air infiltration rate is the source of the home’s air change rate ACH with a traditionally ventilated attic.  The air infiltration rate is the volumetric flow rate of outside air into a building, typically in cubic feet per minute (CFM) or liters per second (LPS). The air exchange rate, (I), is the number of interior volume air changes that occur per hour, and has units of 1/h. The air exchange rate is also known as air changes per hour (ACHs).  ACH can be calculated by multiplying the building’s CFM by 60, and then dividing by the building volume. (CFM x 60)/volume.

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) has had a residential ventilation standard since 2003, ASHRAE 62.2.  The ASHRAE 62.2 minimum ventilation rate formula was set at 7.5 cfm per person plus 1 cfm per 100 square feet.

The standard assumes that the number of occupants in a home equals the number of bedrooms plus one. The ASHRAE 62.2 asserted that the formula used to determine the minimum airflow rate of ventilation equipment was based on the assumption that all homes deserve an “air infiltration credit” of 2 cfm per 100 square feet.  This was the assumption that the homes in and before 2003 had a good amount of air infiltration.  The homes built today with or without the use of SPF insulation are much tighter and have a substantially reduced air infiltration rate.

So while your home’s recommended minimum ventilation rate remained unchanged for many years, ASHRAE has recognized the tighter construction of today’s homes and 10 years after the initial ASHRAE 6.2, there are new changes to the 2013 version of ASHRAE 62.2.  Under the new formula, newer tightly built homes will need to be ventilated at a much higher rate, namely 7.5 cfm per person plus 3 cfm per 100 square feet. This means that for a tightly built 2,400-square-foot home with 3 bedrooms, the minimum airflow rate of the ventilation equipment has jumped 89%, from 54 cfm to 102 cfm.  Long story short, the 2013 version of ASHRAE 62.2 has eliminated the air infiltration credit on new tightly built homes.

Once you apply the Spray Polyurethane Foam Insulation in your attic, your home’s air leakage or air infiltration rate will be greatly reduced.  This is why the SPFA Builder’s Reference Handbook recommends the Test In and Test Out with the use of a blower door to establish your homes air leakage or air infiltration rate.  The Test Out your air leakage or air infiltration rate will determine the amount of outdoor air your home will require to meet the minimum ventilation rate or the ACH of 7.5 cfm per person plus 3 cfm per 100 square feet.

Final Evaluation (Test-Out)

The Final Evaluation (Test-Out) is also a complete evaluation of the existing home after the installation of the SPF insulation.

Complete Evaluation After Installation can include:
•  Air Leakage Testing
•  Repeat blower door test after installation
•  Inspect for air leaks in foam and repair
•  Confirm energy savings projections

The Test Out air leakage testing is once again performed using a blower door to evaluate air leakage and natural ventilation after the spray polyurethane foam insulation application.  This test is then used as the actual as-built air leak and natural ventilation rate.  The blower door test will provide you with your ACH by measuring your home’s actual amount of air leakage.  With this information, you will now know how much additional outdoor air the home will require to meet the minimum ventilation rate.

Among other issues the Test Out as compared to the Test In is the potential need for HVAC Modifications.  The SPFA Builder’s Reference Handbook states that “If application of SPF renders the home to be insufficiently ventilated, work with HVAC contractor to add mechanical ventilation or HRV/ERV.

SPFA Builder’s Reference Handbook clearly informs the application contractor that creating an unvented attic (UVA) with SPF can alter a home by:
•  Reduce uncontrolled air leakage
•  Lower HVAC energy costs
•  Improved insulation performance
•  HVAC system inside the building envelope operates under more moderate temperatures

Most HVAC systems are oversized to account for excess air leakage which directly affects the energy efficiency as well as effectiveness dehumidification.  The application of spray polyurethane foam insulation may actually allow for the downsize of the HVAC system for better performance.

Adjustments or downsizing of HVAC system may be needed to:
•  Achieve Good IAQ
•  Meet the minimum mechanical ventilation rate via outdoor air supply and a dehumidifier or ERV/HRV
•  Avoid short-cycling of AC system for proper dehumidification
•  Supplemental humidification/dehumidification to control relative humidity

To definitively establish the needs for any home once SPF has been installed and the traditional vented attic has been changed to an unvented attic, the use of a blower door must be used to establish the home’s natural ventilation rate and the homes mechanical system requirements must be properly calculated using a Manual J for load calculation, a Manual S for equipment selection, and a Manual D for proper duct design.

Without the known natural ventilation rate, you can only guess at the amount of outdoor air necessary to meet the minimum ventilation rate.  That is if you have even taken the ACH into consideration and added the necessary outdoor air supply.  With the known natural ventilation rate and the new R values, the homes HAVC can be correctly calculated and designed.

You would think knowing the impact of changing from a vented attic to a spray polyurethane foam insulated unvented attic that most home owners are performing the Test In and Test Out procedures.  In actuality, less than 10% of the homes I assess have had any form of Test In or Test Out performance evaluation.  It’s rare that the issue of ventilation or the home’s HVAC system is discussed at all.
Remember earlier in this article we discussed the Guidance on Best Practices for the Installation of Spray Polyurethane Foam states that the contractor and the homeowner should be aware that retrofitting an existing attic by employing an unvented attic assembly technique can result in the existing HVAC system becoming “oversized” in relation to the new demand.

The guidance document also recommends that the application contractor involve an HVAC consultant to adapt the system to the new, more efficient building envelope associated with the spray foam retrofit.

The Guidance goes on to further address the home’s ventilation system:

Important note about air Handlers
If a ventilation system that uses the HVAC air handler fan to provide the needed outdoor air (as is the case in many supply ventilation strategies) is used, it is imperative to ensure that the air handler fan operates often enough to provide sufficient fresh air. During periods of mild weather, or at night in the summer, the air handler fan may not be called on to run for several hours, so the house would get no outdoor air during these times. To address this, control units are now available that will ensure the house always gets the needed ventilation. If the air handler does not operate enough for sufficient ventilation, the monitors will call for the fan to operate and provide sufficient fresh air.

Typically, most homes need for the fan to run for between 10 and 20 minutes each hour to meet the home’s ventilation needs. An example of this type of fan control unit is the Aprilaire 8100.

The introduction of outdoor air not only affects the temperature in the house, it also impacts the humidity in the house. Here in Florida, the humidity can be a critical factor that is often overlooked. Our hot humid southern Florida outdoor air supply will require mechanical dehumidification. It’s critical to include ventilation air in the ACCA Manual J, Eighth Edition (J8) HVAC sizing calculations.

Mechanical System Calculations
Residential Mechanical System guidelines include:

•  Manual J:* Load Calculation
•  Manual S: Equip. Selection
•  Manual D:* Duct Design

Manual J
Manual J is the name for a specific protocol (often called “Heat Load Calculation” or “Cooling Load Calculation“) used to determine how much heating/cooling a home needs to stay cool and dry in the summer and warm in the winter. This load calculation process was developed by engineers in the heating and air conditioning industry and has been used for decades to accurately size heating and air-conditioning equipment. After completing this load calculation process, one can choose a properly sized piece of machinery to satisfy the load.

A Manual-J load calculation report provides three main pieces of information regarding heating and cooling load:
Heating Load: This is how much heat your house will require on the almost-coldest day of the year, in the middle of the night (when there’s no help from the sun). This is the number, or load, used to select a piece of heating equipment.

Sensible Cooling Load: This is the amount of sensible heat (the type you measure with a thermometer) that your system should be able to remove on the almost-warmest day of the year, during the daytime (when the sun is heating up the building). This is used, IN COMBINATION WITH the next load-type, to select the cooling equipment.

Latent Cooling Load: This load describes how much moisture your system should be able to remove under “worst-case” conditions. Worst-case for latent loads are typically when it’s hot and wet outside (daytime in the summer).

These three loads are used to select a piece of machinery that fits the loads (heat losses or gains) of your home. When selecting air conditioners or heat pumps, the two cooling loads should be used. And, the selected piece of machinery should be able to supply the proper amount of BOTH latent and sensible cooling, and be less that 15% over-sized, based on the Manual-J load calculation. This will ensure your system is capable of proper dehumidification (assuming the distribution system is performing properly).

Manual S
Proper equipment selection important and achieving occupant satisfaction is the principal goal of any HVAC design. Occupant satisfaction is maximized when the heating and cooling equipment are the correct type and size to meet the capacity requirements from the Manual J load calculation.  For residential equipment selections, ACCA’s Manual S, is the only procedure recognized by the American National Standards Institute (ANSI). If the Manual J load calculation is done then the next step is to select the equipment that will deliver the necessary heating and cooling.

Undersized equipment will not meet the customer’s comfort requirements at the design specifications.

Oversized equipment will create other problems:
•  Degraded humidity control in the summer.
•  Occupants may suffer the effects of an increased potential for mold growth. These same conditions also may contribute to asthma and other respiratory conditions.
•  The temperature may feel right at the thermostat but the temperature in other rooms will suffer from the oversized equipment going through short operation cycles. Short cycles can cause temperature swings as the equipment over-conditions, stops, then over-conditions, etc…
•  Hot and cold spots between rooms because the thermostat is satisfied but the room is not.
•  Oversized equipment generally requires larger ducts, increased electrical circuit sizing and larger refrigeration tubing. These cause higher installed costs and increased operating expenses.
•  The equipment starts and stops more frequently, this causes excessive wear and can increase maintenance costs more service calls.
In these unfavorable conditions occupants will experience discomfort and dissatisfaction.

Manual D
The next step is the duct design.  For residential air duct designs ACCA’s Manual D is the procedure recognized by the American National Standards Institute (ANSI) and specifically required by residential building codes. Air is the first word in air conditioning. If the network of ducts carrying the air is not properly designed then the health and safety of the occupant are at risk, the equipment could fail more quickly, the energy costs could rise, and occupant comfort might be sacrificed.

In order for home owners to be comfortable, a duct system must be designed to carry the right amount of air, at the right speed, into the right room. If the ducts are the wrong size then the wrong amount of air will enter the room and may cause:
•  The room to be too warm or too cool
•  The air to be too drafty and disturb people while they sleep, eat, read, etc…
•  The air to be too noisy and drown out conversations, TV or radio programs, etc…
•  The air to be too slow – the conditioned air will not circulate or mix well in the room.
•  The fan to work harder, possibly fail sooner, and use more energy to move air
•  The furnace or air conditioner safety devices to stop equipment operation
•  Pressure differentials that may increase energy costs by pushing out conditioned air or drawing in unwanted air

The design and installation of your homes HVAC system with your new spray polyurethane foam insulation SPF insulated home.
The issue of home performance and ventilation must become a more critical aspect of the spray polyurethane foam insulation SPF retro-fit sales pitch.  Understanding the performance changes within a home by altering the attic from traditionally vented to spray polyurethane foam insulation SPF unvented would eliminate a large portion of the SPF occupant odor complaints.

You might be thinking that the new construction homes have it made right?  Well, not so much.  Believe it or not, many new homes are designed with no alterations to the home’s ventilation system in the area of the ventilation rate (outdoor air) and the semi-conditioned attic space.  Many new homes actually have a reduction in size of the HVAC equipment as discussed earlier.  There is absolutely nothing wrong with altering the home’s HVAC system to accommodate the new tighter design and improved R-value; however, there is a huge issue with the builder not taking into consideration the reduced air infiltration, ventilation rate, or air changes per hour ACH. Carbon dioxide, CO2 emissions from the new building material and the dilution of the volatile organic compounds, VOC’s due to the homes ACH.

In a tightly sealed spray polyurethane foam insulation SPF home, the VOC’s accumulate in the attic. The VOC laden warm indoor air rises to the attic as the living space is cooled.  Over time, this accumulation, if not properly diluted, can actually make its way down into the living space from the attic.  The necessary outdoor air supply needs to properly dilute the new construction VOC’s.  It’s the accumulation of these volatile organic compounds, VOC’s that is often directly associated with the SPF.  Fortunately, we have well established studies of new construction homes with traditionally vented attics and no SPF insulation.  These SPF free new construction VOC’s can then be compared to the samples collected from new construction homes with SPF insulation and unvented attics.  If the SPF is bad, the VOC signature will be different than that of a traditional home with no SPF. It seems simple right?  Well, there remain those that sample heavy and look at nothing when it comes to SPF insulation and simply point to the SPF insulation without addressing the home as a whole.

When assessing the condition of any home with SPF insulation and occupant complaint, the home must be inspected as a whole.  The inspection must include the design and performance of the home.  For these new construction inspections there are two specific areas of concern other than the physical inspection of the installed SPF.  First, is the home’s ventilation rate.  We need to know what the home’s ACH is and we need to know if we are at least attaining the minimum ACH recommended by the ASHRAE 62.2.  Second, is the ventilation design of the semi-conditioned attic space.  How is the homes semi-conditioned attic being addressed and ventilated?

These are the primary factors in a home’s ability to properly condition and maintain the indoor environment.

No air circulation in the unvented attic will lead to an elevation of heat, humidity, and VOC’s.  There must be a specific method of circulating air through the semi-conditioned attic space.  If you don’t take ownership of this space in your ventilation design and you assume that the space will be passively semi-conditioned, be prepared to meet me on site at a future date.  We’re not talking about fully conditioning the space by installing supply and return vents in the attic. You need to move air through the semi-conditioned attic.  If you don’t, the attic simply isn’t semi-conditioned.  It’s unconditioned unvented attic space that will soon be a source of odor and occupant complaint.

So you may be asking just how we establish the new construction ventilation rate and method of semi-conditioning the attic.

Final Evaluation (Test-Out)
The Final Evaluation (Test-Out) is also a complete evaluation of the new-construction home after the installation of the SPF insulation.

Complete Evaluation After Installation can include:
•  Air Leakage Testing
•  Blower door test after installation
•  Inspect for air leaks in foam and repair
•  Confirm energy savings projections

The Test Out air leakage testing is performed on the new construction home by using a blower door to evaluate air leakage and ventilation with the unvented attic insulated with spray polyurethane foam.  This test is then used as the actual as-built air leak and natural ventilation rate.  This test and amount of measured actual natural ventilation will tell us exactly how much additional outdoor air is necessary to meet the minimum ventilation rate.  The SPFA Builder’s Reference Handbook states that “If application of SPF renders the home to be insufficiently ventilated, work with HVAC contractor to add mechanical ventilation or HRV/ERV.”

You hear the real estate professionals repeating it’s all about the “Location, Location, Location.”  Well the indoor air quality guy says it’s all about the “Ventilation, Ventilation, Ventilation!”

So at the risk of being overly redundant, ventilation cannot be stressed enough in a home with spray polyurethane foam insulation and an unvented attic.

Any home with spray polyurethane foam insulation and an unvented attic must have a method of semi-conditioning the unvented attic to provide the necessary air circulation to prevent the accumulation of heat, humidity, and VOC’s.  That can’t be found in expensive air sampling for VOC’s.

Any home with spray polyurethane foam insulation and an unvented attic must establish the necessary minimum ventilation rate necessary to prevent occupant complaint while providing good indoor air quality.  That can’t be found in expensive air sampling for VOC’s.

However, both can be identified by measuring the homes performance and the use of a blower door test.  And both can be improved and/or corrected once the actual performance testing has been completed.

So reduce your carbon footprint and save those energy bucks.  Spray polyurethane foam insulation is a great home improvement method of saving energy.  Just remember one thing; if your home is ventilated the same way after the installation of spray polyurethane foam insulation you haven’t finished the home improvement process.

Ventilation, ventilation, ventilation……………..

To learn more about Mr. Lapotaire or Indoor Air Quality Solutions & Microshield Environmental Services, LLC, please visit www.FloridaIAQ.com, email info@FloridaIAQ.com or call (407) 383-9459.

About Indoor Air Quality Solutions & Microshield Environmental Services, LLC

Since 2001, Florida residents have turned to the indoor environmental experts at Indoor Air Quality Solutions & Microshield Environmental Services, LLC.  The family owned and operated companies, based in the Orlando area, offer a comprehensive approach to identifying and correcting comfort and indoor air quality problems.  Their expert staff utilizes the latest technologies and industry recognized standards to identify and resolve indoor environmental issues.

John P. Lapotaire, CIEC

#IAQS

 

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Posted by John P. Lapotaire, CIEC