NC 2009 IEQc5: Indoor Chemical and Pollutant Source Control

I would suspect the LEED review won't have heard of the benefits of using solid ink technology. If you can prove that the technology emits little to no VOCs1. Volatile organic compounds (VOCs) are carbon compounds that participate in atmospheric photochemical reactions (excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides and carbonates, and ammonium carbonate). The compounds vaporize (become a gas) at normal room temperatures. 2. A molecule containing one or more carbon atoms that tends to evaporate (volatilize) into the air at typical ambi­ent conditions. Some legal definitions of VOCs are restricted to those that react with sunlight to generate smog. Some VOCs are carcinogens, suspected carcinogens, or known irritants at typical levels., etc and has no adverse effect on IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors. then you may be able to get away with not exhausting the room.
I'd recommend including a detailed document showing measured IAQ benefits of using solid ink technology.

Green Builder, first question is whether you should be doing LEED for Homes since it's residential. But assuming you made the right call there, the MERVMinimum efficiency reporting value. 13 requirement has always been a bugaboo for multifamily and hotels, as we note in our guidance above under the Bird's Eye View. I am not aware that this has been resolved.

I agree Tristan- I have never seen anyone successfully implement an alternative compliance path to using MERVMinimum efficiency reporting value. 13 filters, except potentially in the case of electrostatic filters which seem to be potentially acceptable, but I have not seen a fast and hard example of those being accepted yet either. Reviewers have, in the past, simply said that this credit is unavailable if you can't meet the MERV 13 requirement.

I'm facing the same difficulties for LEED Homes which the duplex is using VRV system. We can't find any VRV product can install MERVMinimum efficiency reporting value. 13 and provide sufficent static pressure...

Any suggestion is welcome.

Medium or High Static Ducted Fan Coil units (Mitsubishi, Daikin, LG, etc) have 0.6-1.0" of static on some of the larger models. To allow for the MERVMinimum efficiency reporting value. 13 you could potentially build an oversized plenum box behind the unit that is big enough to reduce the FPM across the filter. Then you may have enough static.
You don't have to get every credit. That's why LEED give you many credits to choose from.

Dario,

We do have conversations regarding this earlier and in the v2.2 forum. The entryway systems are best if used with a floor drain. I think roll out mats are a viable option if they can be combined with the same Schools requirement for self-maintained mats.

We used a combination electrostatic and media filter called Strion. That product is rated for MERVMinimum efficiency reporting value. 15.
http://www.strion.com/productdetails.asp

I think that as long as you can show that you have at least matched if not exceeded the ability of a gyp. board hard lid ceiling to prevent air movement between spaces you should be successful with the credit.

Hi Shelley,

In my opinion unfortunately not. User guide has on page 513 description of entryway systems says that:
"entryway system must extend 10 feet from the building entrance into the building interior..."

Of course you can go threw special circumstances path bacuse it might depend i.e. on project location or design of entrance overhang.

EunChung,
It seems as though you are correct. Here is a link to the "LEED Addenda" website.
http://www.usgbc.org/DisplayPage.aspx?CMSPageID=2200#BD+C
Because this is new legislation I can only give you my interpretation:
The intention of the correction is to clarify where the MERVMinimum efficiency reporting value. 13 filters should be located inside an AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. that supplies OSA and recirculate air. The filter should not be at the OSA damper, but instead downstream of the mixing of the return air and the OSA to filter both the OSA and recirculated air.
However, an indoor fan coiling unit or heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. that is recirculating air to condition a space would not require MERV 13 if it is not pulling air directly from outside. Even if there is a DOAS providing OSA air into a mixing boxing in the back of the FCU/heat pump, it should still not require a MERV 13 filter (only MERV 8 for ASHRAE). The MERV 13 filter would be in the DOAS.

Walk Off Mats along with a contract for regular cleaning have historically been acceptable for this credit. So, I think that you should have a very strong case for compliance as long as the lease language requires 10 feet of mat at each entry as well as regular cleaning. You won't know for sure until you submit the credit this way or pay for a LEED Interpretation, but based on past interpretations, you should have a high chance of acceptance. I do not believe that the size of these spaces will help or hurt you in any way, since the credit requires systems at all entries.

If the technical rooms are occupied regularly or even occasionally, I wouldn't recommend transferring air from an underground garage as a means of ventilation. Air from an underground garage (unless open on 2 sides/what code requires locally for the garage to be considered naturally ventilated) isn't fresh air.

I don't know if this question applies to IEQc5?

Caroline- the requirements for this credit as written are a little vague about the acceptability of walk-off carpet. However, we have had many projects where we have used it without additional roll-out mats and received the credit with no problems.

Exhaust (cfm) / area (sq.ft) is correct.

For differential pressure you take into account the supply cfm.

They will likely have to run all the time in order for the pressure differential to be maintained around the clock as required by the credit.

Okay, I'll give you my thoughts to stimulate comments. Since PTACs are self contained HVAC units, how is the building naturally ventillated in your opinion? The spirit of the credit is to keep contaminants out of the interior environment. How are you doing this with the PTAC? How is this done on naturally ventillated buildings? If it were my project, I would likely consider the PTACs as HVAC equipment and look for a filter on the outdoor air. But I am not a mechanical engineer and do not know the finer points on this issue. However, if you can address how the spirit of the credit is maintained with your solution, then you can likely make a good case to the reviewers.

(PTACs used not to be eligible for this credit, as MERVMinimum efficiency reporting value. 13 were required on return air stream which was impossible considering the unit.)

Now, concerning filters required on outside air stream:
The PTAC (Packaged Terminal Air Conditioner) is conditioning the air but is not bringing outside air in the dwelling unit. Thus it is not bringing any contaminants to the environment. That's why we call out those spaces "naturally ventilated".
However, we were concerned that the manually operated damper located on the PTAC could be an issue, but it should be considered as a trickle vent more than anything else and in this case we are meeting the credit requirements.

Hi Amanda,

Have you already applied for your design review? I have a very similar issue regarding this credit and would want to know more about the review you got from GBCI. I hope you could share if ever. Thanks

Please let me know too, would be very helpful information!!

Anyone?

George, did you ever get any clarifications? I'm wondering what is meant by "surrounding spaces" -- does that mean the building on whole has to be positive? Or is it simple saying that when the door is open, you need a minimum of 5 Pa pressure differential.

Please let me clarify, some of the interior entryways have carpeting, do they still need to have matting placed on top of the carpeted areas

Yes- if it is regular carpet you will still need some sort of entryway system. I have been successful using specially made carpet that is designed to be a walk-off surface as an entryway system, but you will definitely not be able to get by with just regular carpet.

Michelle, you should find other discussions of this topic earlier on this forum. This approach seems to be well-accepted, provided there is proper weather protection for the outside portion, so it stays effective.

We have the same question on one of our projects. The 2009 BD&C Reference Guide indicates that "Entryway systems must extend 10 feet from the building entrance into the building interior" and I intrepret that they must be entirely inside the building. While this was a common practice to have this system both on the outside and inside in the past, and makes some common sense, will this be allowed given the new language. The old reference guide was not as explicit on location of the entryway system as the new reference guide. I'm not seeing anything posted yet concerning this in the new CIRs. Any advice?

Cindy, it's my understanding that a weather-protected exterior entryway is equally allowed in 2009 and v2.2.

On the form for this credit, you will have to check a box that says: "Supply air systems, including both outside air and return air delivered as supply, serving all regularly occupied areas are sized to accommodate filtration media with a MERVMinimum efficiency reporting value. rating of 13 or better. New filtration media which meet this MERV rating will be installed prior to occupancy." The strategy you are describing does not seem to be in line with honestly checking this box on the form, so I would recommend that you make sure the MERV 13 filters are installed before building occupancy.

Per LEED interpretation inquiry number 2130 dated 4-25-2008:
...meeting the requirements for weekly cleaning of roll-up walk-off mats by internal maintenance staff, in lieu of an outside contracted service, is acceptable.

This ruling however does not apply to LEED NC 2009.

Can anyone tell me why CIRs of past rating systems do not apply to the new rating systems even when the credit intent and language has not changed????

Regina, you've got it right.

I think that you can be successful on this credit if you write a very good narrative and perhaps do a diagram that demonstrates that people will not enter the building you are working on directly. However, is there a problem with providing entry way systems in your phase just in case people do end up using those doors regularly?

Thanks! I'll let you all know if we are successful with the narrative. There are multiple problems with locating mats inside the cancer center. One is the sudden appearance of a dirt collecting floor system inside a hospital and the second is phasing and the slight changing of the connecting corridor over time.

I know I am a little late, but I did find a LEED Interpretation that seems to deal with this issue. It is #5266 in the LEED Interpretations database on the USGBC website.

I saw that but it seemed like the first entry had entry grilles and then you did not need them into the project building. Here we have an entry building that does not have entry grilles and a project building that also does not have entry grilles.

George- are there any man doors into the basement floors? If so, these may require entryway systems. Also, I would anticipate putting entryway systems in any areas where people will be moving from the garage area to the mall area as this is essentially an exterior condition.

George- are there any man doors into the basement floors? If so, these may require entryway systems. Also, I would anticipate putting entryway systems in any areas where people will be moving from the garage area to the mall area as this is essentially an exterior condition.

Yes Allison, there are main doors. In fact, most of the visitors will enter the mall through the basement floors.

Many thanks!

You could try to submit it, or request a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide, but I have not heard of the 10-foot requirement being relaxed for existing building or other circumstances. Not all credits work for all projects, as they say.

I am working on a project with the same issue. Our vestibules only have 6' of travel from one set to another. Would it be possible to start the walk-off mat after you pass through the second set of doors that actually lead into the building or is LEED pretty specific that the walk off mat must occur upon "immediate" entry to the building?

Christopher, there is a not a requirement limiting the walkoff mat to the vestibule area. However, you would need to make sure that anyone walking in would get 10 feet of trackoff in their main line of travel—so if they could enter the doors and then veer to the left or right and miss the mat, you would need to make it wider.

Yes- I would say they are looking for average over time which factors in different occupancy schedules and system modes. I would think that minimum would occur at times when the system is setback.

I have used an ASHRAE equation for this. See 2007 HVAC Applications handbook, page 52.5, eqn 8. Given airflow (room exhaust) and flow area (door undercut or other inlet), you can calculate differential pressure.

I am also confused on this credit. It still doesnt seem like anyone knows exactly what LEED is looking for pertaining to Average Pressure Differential and Minimum Pressure Differential (with doors closed) and how to calculate the values.

Any thoughts on this?

In one our projects, the M&E team have used the ASHRAE equation Sarah is referring to (i.e. Q= 776CA √2∆P/p).

I am guessing that the equation above gives us the average pressure differential. But how can we get the minimum pressure differential?

Anybody ?

Has anyone used the ASHRAE Applications equation to calculate the average pressure differential and had it approved by USGBC? I think Eqn 9 in the 2007 ASHRAE applications (Q=2610*A*√∆P) is appropriate. I've found that this equation corresponds to Figure 2.2 (Relationship between Airflow Offsets, Differential Pressure, and Effective Leakage Area) of the Health Facility Commissioning Guidelines book.

Also, my systems are either running continuously, or they are off, so I am assuming my minimum pressure differential equals the average pressure differential. Has anyone filled out the form to show that average pressure differential and minimum pressure differential are the same, and had it approved by USGBC?

Other thoughts for how to calcule the minimum pressure differential would be appreciated. Thanks.

The ASHRAE equation above is for Pressure (∆P) in "Inches of water." The equation for pressure in PA would be:

Q=165.5*A*√∆P

Here is an example scenario:

3 foot wide closed door with a 0.5" undercut
A=0.125 ft
∆P=5
Solve for Q (Air Flow in CFM)

Q=165.5*0.125*√5 = 46.3 CFM

In order to ensure this room has a negative 5 PA differential pressure to an adjacent space you need to have roughly 50 CFM exhaust (Exhaust CFM - Supply CFM). Area of the room is irrelevant for this equation but for LEED and local building codes you may also need to ensure that you have at least 0.5 CFM/SF exhaust.