Active Experts
Tony Gill Rick Karg Bob Scott Cal Steiner
From: Bill Beachy
Category: Health and Safety
Subject: ASHRAE 62.2 and Multifamily
Question: Should ventilation fans in a multi-family building be set the same for all units on all floors, especially if the CFM readings differ from the lower and upper floors?
Answer 1: First, I am going to assume that this question has to do with whole-building ventilation, rather than local ventilation intended to exhaust moisture from bathing activities from bathrooms and cooking related pollution from kitchens. For multifamily buildings, the ASHRAE 62.2 committee has defined the word “building” in the term “whole-building” to mean “single dwelling unit”.
For whole-building ventilation, ASHRAE 62.2-2010 does not specify that ventilation rates should be set at the same flow rate for each unit in a multifamily building, nor does it specify a method of determining this ventilation rate, other than the procedure used for a single-family buildings.
Because the ASHRAE standard is silent on this issue, I will express my opinion. It is important to understand that my opinion does not necessarily express the sentiment of the ASHRAE 62.2 committee nor the DOE low-income weatherization program’s policy regarding ASHRAE 62.2-2010. OK, here goes: Because it is difficult in multifamily buildings to be certain whether “infiltration” as measured by the blower door is from outdoors or from other apartment units; size the ventilation flow rates assuming no infiltration credit, based on the square footage and number of bedrooms. Note that the ASHRAE 62.2 committee has passed an addendum that will be part of the 2013 edition that specifies exactly this, so this position can be considered the view of the committee members, even if this addendum is not a part of the version of the standard required by DOE.
Rick Karg with the wise and kind help of Paul Francisco
ASHRAE 62.2 committee members
Answer 2: About the only thing I could add is that if they made an honest attempt and could not find an appropriate sone fan, install the next best fan. I would then get a waiver from the state and document all the searches and info that went into the decision to go with a lesser fan.
I have not had the time to research this properly however, so I’m relying on their info that a low sone fan cannot be found for mobiles. I would, if I were the state, receiving the request for the waiver, ask if they contacted several fan companies for advice.
- Cal Steiner
From: Dan Auer
Category: Technical Tools
Subject: Bath Fan Controls
Question: I am looking for a fan control that will have the fan run a few minutes every hour. I have installed the airetrack and am now hearing of a smart switch. Do you know this porduct or alternates, please advise.
Answer: I’m not aware of a specific “smart switch” but there are several out there that are programmable both for fan speed and cycled run time. Most have an override to boost to full speed when desired. The EFI website catalogue is a good source for what’s generally available. Try
http://www.energyfederation.org/consumer/default.php/cPath/39_766.
-Tony Gill
From: Henry DeWerth
Category: Technical Tools
Subject: Balanced Return Air Pathway
Question: If an agency bid proposal included a line item that simply stated "install jump duct in all bedrooms" - in this scenario the supply ducts are in conditioned space and the Building Code terminology is "transfer ducts" would it not be considered prudent to install RAp devices in the partition wals to keep the return air in conditioned space versus running flex duct runs in an unconditioned attic to a common ceiling grill. We are in a hot humid Florida climate and the attic temps can be 140° at times. We think that keeping the return air ducts in conditioned space would yield higher efficient installation and reduce the loads on the heat pump. Would this be true? Would this method be preferred by DOE on a heat pump change out? It would also cost less to implement.
Answer: A jump, jumper, or transfer duct serves the function of 1) allowing a free return-air pathway so that the space conditioning system can do a more effective job of conditioning and 2) minimizing pressure imbalances in rooms with closed doors during air handler operation. In some cases, doors can be undercut rather than installing transfer ducts. Clearly in the case here, transfer (jump) ducts are being specified rather than undercutting doors; this is preferred to undercutting.
It is always best if ducts can be kept within the thermal/pressure envelope of the dwelling. This minimizes heat transfer to and from conditioned air in the ducts and is likely to make any duct leakage less of an energy drain. So it would be more efficient in Florida to install transfer ducts in interior walls rather than through the hot attic. This will reduce the heat pump loads – summer AND winter – and save energy. Another advantage to keeping ductwork out of the attic is the elimination of the possibility of condensation on the outside of the ducts during cooling season.
Because transfer ducts are often installed to serve bedrooms, it is important be aware of the movement of sound. If a transfer duct consists of two grilles across from one another in a partition wall, sound will move freely through this direct “hole”. A better method is to vertically offset the grilles on either side of the partition wall stud bay by three feet or more.
Although I don’t speak directly for DOE, I think it is safe to assume DOE would agree with Henry’s ideas for transfer ducts.
-Rick Karg
From: Dean Cibotti
Category: Training
Subject: Strapping a cathedral ceiling
Question: I am wondering if strapping affects the insulative values of insulation? The drywall contractors want to strap, but I am not sure have a 1/2 barrier before the kraft face is a good idea.
Answer: Drywall contractors and many builders prefer to strap ceilings before installing drywall because strapping evens out any irregularities in the joists. For example, if one joist bottom is a half-inch higher than the two adjacent ones, the strapping will eliminate the problem, especially if wood shims are used ensure straight strapping and an even drywall plane. However, this practice does add a ¾-inch to ½-inch air space between the bottom of the insulation facing and the top of the drywall. As it turns out, this space can be beneficial to the R-value if the space has no air flowing through it.
The additional R-value created by the air space is approximately 0.75 with the kraft paper facing. On the other hand, if the fiberglass were foil faced, the added R-value from the air space would be approximately 2.0. The additional R-value from the foil facing can be attributed to the radiant component of heat transfer. That is, the foil reflects infrared energy much more readily than the non-reflective kraft paper. So not only is the strapping a good technique for ensuring a more even ceiling plane, but it can enhance the ceiling R-value.
A warning is appropriate for this strapping detail: It is important to ensure that the air space created by the ceiling strapping is sealed so that air cannot flow through it and thereby eliminate, or more than offset, any R-value gained.
-- Rick Karg
From: Andy Caler
Category: Technical Tools
Subject: ASHRAE 62.2-2010
Question: This question was brought to my attention by one of our agencies here in Colorado. The issue is with how, in the Ventilation section of 11-6, it states "Implementing ASHRAE 62.2 is not required where acceptable indoor air quality already exists as defined by ASHRAE 62.2.” ASHRAE defines "acceptable indoor air quality" as; air toward which a substantial majority of occupants expresss dissatisfaction with respect to odor and sesnory irritation and in which there are not likely to be contaminants at concentrations that are known to pose a health risk. Is this as straightforward as it sounds? Are auditors required to determine if a house currently has "indoor air quality" issues? If no indoor air quality issues are detected, installing ventilation is not required? Thanks
Answer: Let’s begin by quoting the Ventilation action required by DOE Weatherization Program Notice (WPN) 11-6, January 12, 2011: “2010 (or most current) ASHRAE 62.2 is required to be met to the fullest extent possible, when performing weatherization activity. Implementing ASHRAE 62.2 is not required where acceptable indoor air quality already exists as defined by ASHRAE 62.2. Existing fans and blower systems should be updated if not adequate.”
ASHRAE 62.2-2010 defines acceptable indoor air quality (IAQ) as: “air toward which a substantial majority of occupants express no dissatisfaction with respect to odor and sensory irritation and in which there are not likely to be contaminants at concentrations that are known to pose a health risk. (page 3)
Determining unacceptable indoor air quality can occasionally be quite simple, but it is usually challenging. If the air in a house is reeking of cat urine, it is unacceptable. We all know this; it’s simple. If the water heater is spilling, causing 200 ppm of carbon monoxide to enter the home, it is unacceptable. If a waste pipe has broken in the basement, it is unacceptable. High polluting events are usually pretty easy to detect (not in the case of carbon monoxide or radon) and fix. Our health and safety protocols are set up to find and correct such issues. ASHRAE 62.2 is not intended to address these high-polluting events.
The challenges are the more typical cases that might include mold and mildew, formaldehyde emitted from kitchen cabinets, or volatile organic compounds (VOCs) from carpets, paint, and household cleaners. Weatherization personnel do not have the equipment or protocols to detect these problems. ASHRAE 62.2 is intended to mitigate these types of pollution by diluting the household air with fresh outdoor air (whole-building ventilation) and eliminating some pollution at its source (local bathroom and kitchen ventilation). We expect DOE was aware of this when policy makers adopted the use of 62.2 for Weatherization.
Both the definition of acceptable IAQ in ASHRAE 62.2 and the full WPN 11-6 acknowledge that there are many contaminants beyond mold and mildew, formaldehyde, and VOCs that might be of concern. These include, but may not be limited to, radon, carbon monoxide, and carbon dioxide. The Ventilation statement in the WPN 11-6 allows agencies to avoid the prescriptive requirement of installing a fan if they can demonstrate acceptable IAQ on a performance basis. However, it is our interpretation that this demonstration is not fulfilled by a subjective assessment by an auditor. Rather, it must be an objective assessment that holds up to questioning. Essentially, if you don’t want to install a fan, prove why it is not needed. Otherwise, don’t try to subjectively assess whether each home meets the definition of acceptable IAQ, but instead implement the prescriptive 62.2 ventilation.
Interviews with the client should not be used to assess whether a home has acceptable indoor air quality. One reason is that expressed dissatisfaction is only a part of the definition of acceptable IAQ, and there are pollutants that clients cannot sense which are likely to increase in concentration following weatherization if ventilation is not added. A second reason is that the responses from clients will be based on pre-weatherization, rather than post-weatherization, conditions.
The Wisconsin Weatherization Program has been using ASHRAE 62.2 since 2004 and as a result has installed thousands of ventilation systems in low-income homes. Their auditors use the appropriate ASHRAE 62.2 calculations for every job to determine whether to install ventilation, rather than making a subjective determination about indoor air quality. This is the safe way to proceed, at least until a sure-fire and inexpensive method of determining indoor air quality is found.
-Rick Karg, with the generous and expert help of Paul Francisco. Both are members of the ASHRAE 62.2 committee.
From: Randall Olsen
Category: Monitoring
Subject: Kneewall Insulation
Question: We have long required all kneewall insulation to be covered with a housewrap (Tyvek, etc.). We believe this has to do with possible wind washing reducing the thermal performance of the insullation batt (non human contact area). We request your expert opinion and thoughts on installing housewrap over kneewall insulation. Thank you!
Answer: Yes it is always a good idea to cover insulation in a manner that air movement cannot degrade the R-Value, it also helps keep pests out of the insulation. Covering it with house wrap will work. We use John Mannsville comfort therm R-19 or R-13. It is a poly-encased fiberglass batt. We choose to do that as it saves us the labor of installing the house wrap. However, your method is absolutely acceptable.
-Cal Steiner
From: Kevin Simonson
Category: Technical Tools
Subject: Core Sampling of Sidewall Insulation
Question: We are supposed to take core samples to verify density of sidewall insulation. What is the weight of the sample supposed to be? What tools are needed? Is there an industry standard for core sampling? We are supposed to have 3.4 lbs. per cubic foot.
Answer: The important reasons to dense pack insulation are to reduce air leakage through the cavity and to prevent settling. Core sampling can verify the proper density was installed and it can serve as a great training tool.
I have probably done from 200 to 300 core samples on walls where cellulose was blown. I have found it to be a great technique, but it has limitations. Core sampling will give a reliable value for insulation density, but only where the sample is taken; this is important to keep in mind. The core sample at 3 feet above the floor might be 3.5 pounds/ft3, but at 7 feet above there might be little or no insulation.
The density of cellulose insulation determined by the core sampling should be from 3.25 to 4.5 pounds/ft3; from 3.5 to 4 pounds/ft3 is just right. If you are measuring another type of insulation, the ideal density will be different. Blown fiberglass, for example, should have a density of 2 pounds/ft3 or more.
Unfortunately, a core sampling kit must be pieced together; I don’t know of any commercially available kits you can purchase. You can find the parts required for a core sampling kit on my website at
http://www.karg.com/pdf/Insulaton_density/Core_Sample_Kit_document.pdf. Instructions for the use of the kit are included. The “core” I have always used is 2-inch diameter Drain, Waste, and Vent (DWS) copper tubing, 12 inches long. Others use different cores or tubes for extracting the insulation sample. Whatever you use for the core, it is important that your density equivalency table be based on the exact inside diameter of the core. For the core I use, you can find the density table at
http://www.karg.com/pdf/Insulaton_density/Core_sample_chart.pdf. This chart is ONLY for cellulose, not for fiberglass.
I am not aware of an industry standard for core sampling installed insulation. A few quality control experts have told me that in order to get a reliable idea of whether the walls of a house are adequately dense packed, we would have to take about 30 core samples. Of course, for day-to-day weatherization operations, this is not possible.
Don’t ever take a core sample at or within 2 feet of the fill hole where the insulation was blown in. What matters is the density further away from the fill hole; the density 3 to 6 feet from the fill hole demonstrates the skill of the installers and the quality of their equipment.
There are a few other methods for checking density that are easier than core sampling, but not as precise. Because I have never checked the density of blown fiberglass, I am limiting my suggestions to cellulose. First, the finger – or digit – method. Drill a hole in the exterior wall sheathing to expose the blown cellulose. If your index finger is able to penetrate the blown cellulose, it is not adequately packed (probably less than 3.5 pounds/ft3). This doesn’t give you a density value, but it is quick.
Another simple method was devised by Andy Cordova in Colorado; it’s ingenious. I call it the “twisty thing.” This simple tool is a piece of heavy wire (heavier than a coat hanger; similar to the gauge of the wire used to hold up fiberglass batts under floors), 15 inches long. At one end, put a bend at a right angle to create a 3-inch long leg. Do the same at the other end, but put the 3-inch leg in the opposite direction. After the bending is complete, you have a 3-inch leg at each end pointing in opposite directions, with a 9-inch straight piece connecting the two legs. The shape is like the letter “Z”, but the angles are 90 degrees. [Rebecca, can we insert the attached photo within this answer?] To get an idea of the density of cellulose insulation, drill a ¼-inch hole in the wall, inside or out. Insert the twisty thing half way into the hole. Now try to spin it with the exposed leg. If you are not able to rotate it, the cellulose is dense packed. If you can spin it, it is not dense packed. Elegant and simple.
-Rick Karg
From: Joanne Gregory
Category: Technical Tools
Subject: Blower Door Testing
Question: Should auditors conduct Blower Door tests in homes where asbestos is present? If so, will it disturb asbestos fibers where they could then become airborne and pose a health risk to auditors and clients. Please advise ASAP. Is there a policy on this topic?
Asbestos - in vermiculite When vermiculite is present, unless testing determines otherwise, take precautionary measures as if it contains asbestos, such as not using blower door tests and utilizing personal air monitoring while in attics. Where blower door tests are performed, it is a best practice to perform pressurization instead of depressurization. Encapsulation by an appropriately trained asbestos control professional is allowed. Removal is not allowed.
-Bob Scott
From: Tom Vita
Category: Technical Tools
Subject: Exterior Wall Blows
Question: How can you pull aluminum siding off to do a wall blow--without damaging the siding?
Answer 1: Removing aluminum siding without damaging it is a challenge. I have seen some technicians in the field make a mess of it and others consistently remove it without damage. As you probably know already, if you dent or crimp it, you can’t hide it.
No matter what the siding type, it is a good idea to start the removal process on the back of the house or in another inconspicuous spot. This allows you to get a “feel” for how it is going to come off without damaging an area that will remind the homeowner of you every time they enter the front door.
If you can find a person at another agency or a contractor that has a good removal technique, ask if you can help them out for a day or a half day. This is not knowledge you can learn from a book or in a classroom; you must be there to watch and try it for yourself to get the hang of it.
By the way, some technicians cut the siding just under the bottom-of-the-clapboard protrusion with a vibrating cutter like the Fein MultiMaster oscillating tool. This makes a clean, narrow cut that is then caulked after the siding is face nailed in place. Don’t assume this is an acceptable method until checking with the appropriate people within your organization. Surely careful removal and replacement is the preferred method.
-Rick Karg
Answer 2: I’m with Rick on this one up to finding someone who can successfully remove/replace aluminum siding. I’ve seen the results from a number of people who claimed they could and have to say, none of them could; there was always observable damage to one degree or another. If there is a capable person available – perhaps a really good CAA crew person or someone in the siding trade, it might be possible to create a demonstration video or move them around to do trainings, otherwise, I would advocate for sticking with undercutting the lip as Rick describes below.
-Tony Gill
Answer 3: The word I get from the real “experts” in the field is this:
a. When you remove it. Take your time, be careful
b. Remove the Styrofoam from the back of the siding before you put it back
c. When you put it back take your time again.
d. Use some soap on the edge so it snaps back on a little easier.
One other suggestion was, have the same person put it on that took it off, then they will be more careful. Other than that, experience goes a long way.
-Cal Steiner
From:
Margaret Donnelly
Category:
Health and Safety
Subject:
Heater Enclosures
Question:
In a single family home, atmospheric draft water heater in hallway (adequate room volume). Direct vent natural gas heater in living room (no ducts). dryer in hall way. Does the water heater need to be enclosed?
Answer:
Per national code, if it isn’t in a bathroom or a bedroom: no. (local code may be more restrictive) The real issue is, does the water heater draft properly under all conditions? To test, put the house in winter-time conditions, turn on all exhaust appliances – including the drier – open and close interior doors and – measuring from the area containing the water heater to the exterior with a manometer - record the lowest depressurization achieved. That’s the worst case depressurization. Check that number against the applicable state technical manual depressurization limit for naturally vented gas water heaters and act accordingly. (accordingly: if the greatest depressurization > than the limit, provide make–up air or replace water heater with a sealed combustion unit; if depressurization < than limit, verify that the water heater drafts properly by firing it under the most adverse condition and checking with a draft gauge or chemical smoke at the draft hood.) Client education and a good CO detector are mandatory!
From: Johnny Field
Category: Training
Subject:
LSW Practices
Question: Our weatherization workers are trained to work as EPA Certified Renovators using the EPA/HUD curriculum. Will these workers also need to attend a class that uses the LSW Minimum Standards Training Curriculum? We also may have some workers on site that have not attended the EPA Renovator training but are supervised by a Certified Renovator. EPA allows these worker to receive on the job training by the Certified Renovator. Does DOE see this as sufficient training or will they need to attend the 8 hour LSW Minimum Standards Training.
Answer:
DOE Grant Guidance WPN 10-1 states:
Grantees should be advised, Certified Renovator courses are generally created for renovation/remodeling contractors and do not include all aspects of Lead Safe Weatherization (LSW) – the methods and techniques that reduce the spread of dust specific to typical Weatherization activities. Because Certified Renovator courses do not cover all LSW practices, DOE requires
ALL
Certified Renovators be trained in LSW prior to working on pre-78 housing. Further, since DOE requires LSW in all pre-78 housing, all crew workers must also be trained in LSW before working in pre-78 housing.
DOE further requires all Grantee Monitors/Inspectors be Certified Renovators in order to effectively monitor against the EPA requirements AND trained in LSW in order to effectively monitor against LSW minimum requirements.
-Bob Scott
From:
Ryan Harrison
Category:
Technical Tools
Subject:
Caz test
Question:
Propane water heater with sealed combustion in it's own closet with combustion air from attic, Furnace on roof, gas range. Two bathroom exhaust fans pushing 80cfm each, laundry room exhaust fan 50cfm and range hood 200cfm, with 144cu inch fresh air opening to help bring down caz to -4.2pascals. We are negative -1.2 pascals over limit. Is there any flexibility here. I know negative or positive 3pascals is the limit on caz, but there should be flexibility here based on the type of appliances. Please contact me. Thank you much Ryan.
Answer 1:
Ryan, here is my understanding of the scene:
Ryan, here is my understanding of the scene:
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The propane water heater is a direct-vent, sealed combustion appliance.
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The furnace is on the roof.
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The gas range is not vented.
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The bathroom, kitchen, and laundry exhaust fans are depressurizing the house and/or CAZ to -4.2 Pascals with the 144 square inch air vent open.
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I am not sure whether there is a clothes dryer or not. If there is, it should be operating during your testing.
Based on the details you supplied, I don’t think you have a problem.
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If the CAZ is the water heater closet, the depressurization limit is not being exceeded because the water heater is direct-vent, sealed combustion. This means that this appliance is safe with the CAZ pressure of -4.2 Pascals.
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If the CAZ is where the furnace is -- outdoors, there is not a problem because the furnace is on the roof where the house depressurization due to the exhaust fans will not affect it.
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If the CAZ in the kitchen where the gas range is, there is no problem because the gas range is not vented, so it cannot be back-drafted by the exhaust fans.
Regarding your comment about the flexibility of this analysis; as you know, there are several parts to combustion safety testing. Your question addresses only the CAZ depressurization limits for vented combustion appliances. Other parts of the testing usually include checking for spillage within the first few minutes of startup, checking for adequate draft at steady-state, and measuring carbon monoxide levels at steady-state (when the vent temperature stabilizes).
Weatherization programs might have slightly different methods and thresholds values for these test procedures, but all are using fairly similar procedures. Clear failure of one or more of the required tests should always indicate the need for the technician to fix the problems. However, in cases where the combustion safety testing indicates a situation where a combustion appliance barely fails or barely passes, it is up to the technician to decide whether allow it to pass or report it as failed. This is where the flexibility is; in the experienced judgment of the technician. We owe it to our clients and customers to always be cautious with our judgments and to keep their safety as our primary concern.
-Rick Karg
Answer 2:
Ryan is correct. There should be – and is – CAZ test flexibility depending on the type of appliance. CAZ test requirements don’t apply to a sealed combustion appliance. The point of sealed combustion is the combustion appliance gets its combustion air directly from the outside and also exhausts its byproducts directly to the outside. It’s uncoupled from the home’s interior and therefore not affected in any way by either pressure in or depressurization of the space it occupies.