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Some common misconceptions
This credit can be fairly difficult to understand at a glance. So let’s start by getting some common misconceptions out of the way.
One common misconception is that this credit specifies or prohibits a certain refrigerant type. That was true in early versions of LEED (and is still the case in the prerequisite, EAp3). For this credit, there are both HCFCsHydrochlorofluorocarbons (HCFCs) are refrigerants that cause significantly less depletion of the stratospheric ozone layer than chlorofluorocarbons. (hydrochlorofluorocarbons) and HFCs (hydrofluorocarbons...
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60 Comments
GWP / ODP of Water & Lithium Bromide
In our project a absorption chiller will be used to cover part of the cooling load. The chiller will run on lithium bromide / water solution. In this case, water is the refrigerant.
Water is a natural refrigerant with GWP, but my feeling says in the LEED Online form GWP and ODP should be set to 0. As far as I know the water content in the atmosphere depends on temperature mainly and not on water vapour released by humans.
Any hints or comments?
VRF Lifetime
Dear all,
I just wanted to double check that the VRF system lifetime is 15 years (considered a packaged AC). Is this true?
Thanks,
That's how I would interpret it.
Is Tenant commercial refrigeration units included ?
I'm currently working on a LEED NC project on a central university library projects. While the HVAC centralized cooling unist comply with the requirement, a question has arisen about tenant equipment.
On the first floor, there will be comercial spaces leased for supermarket and general retailers. The supermarket include high volume (both in power and refrigerant amount) of commercial refrigeration units.
Should we include these, while the units are built and managed by the tenant?
Yes, I believe they would need to be included. If they are new, they should comply.
High Efficiency Chiller Refrigerant Charge vs. Capacity
It seems to me that an unintended consequence of selecting a high efficiency water cooled centrifugal chiller ( both R-123 and R-134a) is the greater difficulty keeping impact per ton below 100 needed to achieve EAc4. I believe the reason is as the chiller manufacturers push their compressor/condenser/evaporator combinations to achieve high energy efficiency(low kw/ton); they find the need to add more and more heat exchanger surface. Along with heat increased heat exchanger surface comes more refrigerant. I have seen this play out with chillers from two major MFR. using two different refrigerants. Has anyone else had any experience with this phenomenon??
Tonnage Associated with Energy Recovery Equipment
Is the tonnage requirement for the credit supposed to include compressor capacity only or can additional capacity from energy recovery devices be included in the tonnage?
Rebekah, I believe tonnage would include the whole system capacity.
Daikin VRF Leakage Rates
We are submitting a project under CS 2.0. The template will allow us to change the default leakage rates. We are using daikin. I have read in previous posts about providing manufacturer documented leakage rates but have been unsuccessful in obtaining such documentation from daikin. Is there such a document available? Thanks in advance!
Brian, I haven't seen such a document from Daikin—did you find it?
Note that, per previous LEED Interpretation (ID #1540), "All projects registered after April 30th must use default values for leakage rates."
http://bit.ly/vh3NHz
Central Plant Question
Scenario: Campus new construction projects which are connecting to an existing central plant for heating and cooling. The reference guide and DES guideline are clear that you must consider the refrigerant in the central plant (or District Energy System) when doing the calculation. One of the variables in the EAc4 calculation is service Life of equipment. These values are provided for new equipment by the ref guide and ASHRAE.
Question: For the existing central plant equipment, should the service life be the full rated service life as published by ASHRAE or a prorated life accounting for the current age of the equipment (since it is not new)?
The GBCI responded to my question and said that I should use the Reference Guide and ASHRAE values and not the actual age of the equipment. Wanted to share this information with everyone.
Gross ARI rated cooling capacity
Hi,
Where should I get the "gross ARI rated cooling capacity" for air to water heat pumps ? This is not covered by ARI 550/590 which usually applies to chillers. On the technical data sheets, I found the "nominal cooling capaciy" following Eurovent standard.
Do you think I can use this value ?
Thanks
Aurélie
I think the nominal cooling capacity is close enough for this calculation.
Heat Pipes
Here's a stumper for y'all.
A "heat pipe" uses refrigerant migration (without compressors) between two coils for heat recovery. If I am using a heat pipe system, do I include that refrigerant charge in my calc for EAc4? If I do, how do I determine the tonnage?
There doesn't seem to be a lot of practical, usable numbers available for this technology. I'll let anyone else jump in here, I have no experience with heat pipe.
I'd say if the refrigerant is part of the HVAC&R equipment then it should be included in the credit calc. I see one company uses de-ionized water.
Regarding tonnage, I thought this was a load calculation based on climate, internal loads, and building envelople. A ton of cooling is equal to a ton of cooling, regardless of the equipment doing it. If a room needs 10 tons of cooling then that's the size of the heat pipe system specified.
The type of heat pipe, ambient temp, and orientation will affect how much energy it can transfer. I think it's up to the manufacturer to tell you a tonnage. And you may need to do a watts to ton conversion.
Interesting links I found. Now I know a little more about heat pipes.
http://www.enertron-inc.com/enertron-resources/library.php
http://www.fsec.ucf.edu/en/publications/pdf/FSEC-FS-27-84.pdf
FM-200 (HFC-227ea) as Clean Agent Fire Suppression
Clean agent fire suppressant materials have no bearing on the Life Cycle Ozone Depletion calculation as they are not used as refrigerants. However, there is a statement in the Enhanced Refrigeration Management document from the LEED Reference Guide that in order to achieve the credit, fire suppression systems must avoid the use of halonsHalons are substances, used in fire-suppression systems and fire extinguishers, that deplete the stratospheric ozone layer., CFCsChlorofluorocarbons (CFCs) are hydrocarbons that are used as refrigerants and cause depletion of the stratospheric ozone layer., and HCFCsHydrochlorofluorocarbons (HCFCs) are refrigerants that cause significantly less depletion of the stratospheric ozone layer than chlorofluorocarbons..
Our project, a massive Mission Critical Facility, is currently planning on using FM-200 (HFC-227ea) which is a heptafluoropropane, and not listed as a Halon, CFC or HCFC.
Has this Clean Agent Fire Suppression been approved for usage and do you anticipate any problems in our approach in utilizing it?
The reference product (HFC-227ea) does have a Global Warming Potential of GWP=3,660, but likely unrelated to his decision.
Any help would be awesome!
Hi Ted,
It's a good question and though specific fire suppression systems don't go through a pre-approval process for LEED, the system is compliant by virtue of being an HFC rather than HCFC, CFC or Halon. That is the critical piece for this credit. Also, this data sheet http://www.fike.com/pub/fpsdocs/c.1.07.01.pdf notes that it's a good replacement or halon systems.
I still don't understand how
I still don't understand how I am supposed to find out or calcuate int Rc? Is this a number you get from the manufacturer? Which in my case is Panasonic and I doubt I will be able to get a hold them. Any help?!!
Nena,
Can you get the cooling capacity (in tons) and the total pounds of refrigerant in a full charge (lbs of refrigerant) for the equipment from manufacturer cut sheets, technical information documentation, or the company website? Refrigerant charge is calculated by dividing the total pounds of refrigerant in a full charge by the cooling capacity of the equipment. So the resulting value is in units of lbs/ton.
Is the original charge in manufacturer's spec the same as full charge? I can only find the original charge.
Yes.
SF6 in MV switchgears - Any LEED limits?
Does the SF6 (Sulphur Hexafluoride) insulating gas used to quench the arc in electrical power equipment (MV switchgears) need to be taken into consideration under the EAc4? The credit language states that only the refrigerants in HVAC&R equipment are considered in the calculation. Nonetheless, I just wanted to confirm this as SF6 is a greenhouse gas which has a very large GWP. From my review, there do not seem to be any other LEED credits that would limit the use of SF6. Does anyone know anything to the contrary? Thanks!
Lara, there is a bit more too this credit. It also prohibits fire suppression systems using CFCsChlorofluorocarbons (CFCs) are hydrocarbons that are used as refrigerants and cause depletion of the stratospheric ozone layer., hydrochlorofluorocarbons (HCFCsHydrochlorofluorocarbons (HCFCs) are refrigerants that cause significantly less depletion of the stratospheric ozone layer than chlorofluorocarbons.) or halonsHalons are substances, used in fire-suppression systems and fire extinguishers, that deplete the stratospheric ozone layer.. If SF6 is considered to be one of these, then using it counts here. If not, then I'd say it's not considered for this credit, despite its high GWP.
Is the LEED requirement for HVAC&R equipment OR for any refrigerant that creates HVAC&R for the buildings users? A product that is used for cooling the equipment (not get to warm for example as the one mentioned above) but it is NOT used in any equipment that creates HVAC&R for the building (air conditioner, freezer or comparable). Should that refrigerant be included or not? I do believe so, but please advise.
Thank you!
Include CFCs planned for phase out in calculations
If we have CFCsChlorofluorocarbons (CFCs) are hydrocarbons that are used as refrigerants and cause depletion of the stratospheric ozone layer. in a central chiller plant that have a phase out plan in place for all chillers that have CFCs (as required by EAp3), do we include the CFCs in the calculations for this credit? Or do we not include the CFCs because they will be phased out?
When are they going to be phased out?
I am pretty sure that EAc4 looks at your system as it is, not as you plan it to be.
This was my interpretation as well. The chiller that has the cfcsChlorofluorocarbons (CFCs) are hydrocarbons that are used as refrigerants and cause depletion of the stratospheric ozone layer. is actually non-functional. Is there any guidance on what must be done to existing CFC chillers to make them meet this credit? Does the refrigerant have to be removed from the units if they are non-functional?
Meeting this credit is not a matter of "do this, don't do this." You have to have a system that complies with the impact equation shown above. That said, it sounds like responsibily disposing of CFCsChlorofluorocarbons (CFCs) are hydrocarbons that are used as refrigerants and cause depletion of the stratospheric ozone layer. that you're not using would be a no-brainer way to improve your likelihood of compliance.
VRF Systems and Leakge Rates
In previous rating systems the use of non-default leakage rates were acceptable provided that documentation was provided. For example, Daikin has documented leakage rates below the default values. I have heard "thru the grapevine" that non-default leakage rates are no longer allowed. Is this true?
Based on the template which locks you out of entering a non default leakage rateThe speed at which an appliance loses refrigerant, measured between refrigerant charges or over 12 months, whichever is shorter. The leakage rate is expressed in terms of the percentage of the appliance's full charge that would be lost over a 12-month period if the rate stabilized. (EPA Clean Air Act, Title VI, Rule 608). I would guess that this is true.
I noticed the same issue with the Retail (NC) rating system. The sample credit template for this credit states that non-default values (anything other than 2%) values are not permitted, and it is not possible to alter this value in the calculation table.
However, the GBD&C Reference Guide contradicts the template on this issue. On p.311, it indicates that non-default leakage rateThe speed at which an appliance loses refrigerant, measured between refrigerant charges or over 12 months, whichever is shorter. The leakage rate is expressed in terms of the percentage of the appliance's full charge that would be lost over a 12-month period if the rate stabilized. (EPA Clean Air Act, Title VI, Rule 608). values are permitted with the appropriate documentation. The Retail Reference Guide Supplement does not contain guidance on this credit.
Has this issue been resolved definitively?
Based on the same information in the reference guide that Anders pointed out, it seems clear that you can use a non-default Leakage RateThe speed at which an appliance loses refrigerant, measured between refrigerant charges or over 12 months, whichever is shorter. The leakage rate is expressed in terms of the percentage of the appliance's full charge that would be lost over a 12-month period if the rate stabilized. (EPA Clean Air Act, Title VI, Rule 608).. But it looks like you're best bet is to present the requested documentation through the 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 process and to get pre-approval for the alternative rate. The reference guide does imply that alternative values can be considered during the course of the normal review but that seems like a more risky approach given the direction provided.
Also, because the credit form does not allow input an alternative rate, the onus will be on the team to present the credit calculations through a homegrown calculator that can be reviewed by GBCI.
USGBC/GBCI has stopped accepting "non-default" leakage rates.
Refrigerant Charge
I'm confused about the Refrigerant Charge as a requirement for this credit. The language of the LEED 2009 manual in the "Select Equipment with Efficient Refrigerant Charge" paragraph under Implementation would suggest that Charge values MUST comply with Table 2 in that same section. However, there is no mention of Refrigerant Charge, other than its definition as it applies to the Impact Formula, in the Credit Requirements.
Further more, if you look closely at Sample Calculation 2 for the Office Building, the Rc values for the pony chiller and AC unites are way above what is allowed by Table 2. Yet, it still says the credit is awarded because the Average Refrigerant Environmental Impact is less than 100.
I'm inclined to think that, as long as my impact calculation comes out to be less than 100, I should be OK even if some of my equipment exceeds the max Rc. Can anyone confirm or refute this for sure?
Kenneth
It looks like Table 2 is an example of maximum refrigerant charge for a single equipment with some assumptions and default leak rate of 2%, and end of year loss of 10%. If you find the equipment installed on your project has lower refrigerant charge, please use the actual number in the calculation. The credit is awarded if the Average Atmosphere Refrigerant Impact is less than 100. It would be very helpful to support all calculations and refrigerant charges with manufacturer data and cut sheets
refrigerant R417 A
Is this possible, to use R417 A in replacement for the R22?
Does it comply with EAC4? I don't see it as a possible refrigerant in the list provided by LEED.
Thanks
My understanding is that R417A is a blend of refrigerants, and that it seems likely to be in the class of refrigerants that can be helpful for earning this credit.
It's important to note that EAc4 does not specifically ban or allow any specific refrigerants. Credit compliance depends on a calculation. The list you're referring to seems like it may just be a reference list of common refrigerants that appears in the LEED Reference Guide.
Will R134a, R407c and R410a always comply ?
Hello,
I realize that there is a calculation methodology outlined in the LEED Guidance in order to determine whether or not refrigerants comply.
However, this methodology assumes that the amount of each refrigerant type (in tons) is known. What if we do not have this figure yet?
Can we simply say that R134a, R407c and R410a comply no matter their quantity since each of them has a Refrigerant Atmospheric Impact <100 ?
Many thanks for the help.
George
I wouldn't be able to tell you offhand whether those refrigerants would be compliant in all typical scenarios.
However, I would emphasiz that compliance with this credit is highly dependent on the calculation that includes the refrigerent charge, so I would caution you from making any assumptions without doing at least a rough estimate of the charge.
How does one estimate the refrigerent charge? Is this something you get from the manufacturer of the unit?
Nelina, this question is answered in the Checklists tab above in the Construction Documents section. A number of other helpful tips are also provided there. (This content is reserved for members.)
No, the refrigerant will not always comply because the credit calculations consider the sum of the equipment leakage rateThe speed at which an appliance loses refrigerant, measured between refrigerant charges or over 12 months, whichever is shorter. The leakage rate is expressed in terms of the percentage of the appliance's full charge that would be lost over a 12-month period if the rate stabilized. (EPA Clean Air Act, Title VI, Rule 608). and refrigerant charge, as well as the GHG potential and ODP potential of the refrigerant. It's best to track down each of the required data points (with the help of an 3rd-party expert if necessary) and complete the calculations; GBCI will definitely require this to comply with the credit requirements.
Cooling Capacity of VRF System
We have a VRF system in the building and need to use its cooling capacity to calculate the weighted average for this credit. Which should be taken as the cooling capacity:
- Capacity of outdoor units,
- Capacity of indoor units,
- Capacity of outdoor + indoor units?
The VRF system, as it uses refrigereant for heat transfer between indoor and outdoor units, has a lot of refrigerant charge, so the selection really matters in staying below the 100 threshold.
Omer, this credit looks at the cooling system as a whole so I think you would need to factor in the the total capacity of your units, indoor plus outdoor.
Using VRF (variable refrigerant flow) systems has a lot of benefits, including energy efficiency, but they can be problematic with regards to EAc4 because of the high refrigerant charge. I wrote about these systems in some detail in an article on BuildingGreen.com, by the way.
For VRF systems you should use the capacity of the outdoor units. Think of the system as if it was chilled water, you wouldn't add the chiller capacity to the air handler capacity to describe the size (tonnage) of the system. The same methodology applies here.
Todd, are you sure about that? That doesn't seem consistent with the credit intent or requirements, which looks at pounds of refrigerant used. Chilled water is not potentially ozone-depleting.
I'm prepared to be corrected on this if you have better information, like a successful review, but I want to double-check with you.
Tristan - In my opinion, the cooling capacity of the system is best defined by the capacity of the outdoor units. I used chilled water as an example that most HVAC engineers can relate to. Adding the indoor unit and outdoor unit capacities would overstate the capacity of the system. For example, if the system consisted of a 5-ton condensing unit and five (5) 1-ton fan coil units the capacity of the system would be 5 tons. If the outdoor and indoor unit capacities were added the result would be 5+1+1+1+1+1 = 10 tons. The system is clearly not a 10 ton system.
Make sense?
I see your point from an HVAC engineering perspective, but look at it from LEED's perspective, in which the concern is the tons of refrigerant being used, and the impact on the atmosphere. I don't see LEED drawing the kind of distinction that you're making. I'd want to see some reference to that in the Reference Guide, 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, or a successful review before I was prepared to recommend the approach.
Tristan - There are 2 topics being confused here.
The first is the capacity of the system which is defined in tons of refrigeration (5 tons in my previous example). The capacity of the system is based on the capacity of the outdoor units not the sum of the indoor and outdoor units.
The second is the refrigerant charge which is defined in pounds of refrigerant. The total refrigerant charge of the system needs to be accounted for including the outdoor units, the indoor units, the branch selectors and all of the piping.
Hopefully this gets us back on the same page.
Todd, I think that clears it up, and we're on the same page here.
Commercial Refrigeration Equipment
Hi All--Does anyone know if there is a distinction between upright vs. under-counter commercial refrigeration units? Are under-counter units considered permanently installed? Or will they all need to comply with this credit if they have more than 0.5 lbs. of refrigerant? Thanks, Marian
The distinguishing factor for inclusion or exclusion from the credit is the 0.5 lbs of refrigerant mark. If an upright or under-counter commercial refrigeration unit has more than 0.5 lbs of refrigerant then we would probably include it in the calculation.
I agree with Ben, if commercial refrigerators have more than 0.5 lbs should be taken into account.
But I have a related problem: the refrigerant emploied at a commercial refrigerator has more than 0.5 lbs (HFC 404A), and it does not appear in the template. I do not know, should I consider in the template the refrigerant with most similar characteristics or should I not take it into account??
Interesting issue. I'm asking around, but I would simply send a note to GBCI via the feedback form on LEED Online and ask them what to do. Please post back here with what you learn.
This is the same concern I had. I found this discussion in my search for an answer on the correct way to represent commercial refrigeration units in this credit. Has anyone been able to find a solution regarding this dilemma?
I would send a note to GBCI via the feedback link on LEED Online. They are typically responsive to questions like this. Please post back here what you learn!
I understand EAc4 refers to ODPs in "fire suppression systems"... Does this apply to hand-portable extinguishers?
Lars, I would say it generally applies to automatic building systems (similar to sprinklers), but one could argue that extinguishers should be included. How do their chemicals fare under this credit?
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