Thanks for all the helpful posts. I’ve found answers to many questions here. I have run across what seems to me to be a discrepancy in the LEED 2.2 Ref Guide WE c1.2 Calculations section w.r.t info in the same 1.2 Requirements section and hope someone can shed some light …

WE 1.2 Calculations (page 123 in Ref Manual) I would have expected to have dealt with the “OR” case of the Requirements, but instead say “If the Percent Reduction of Potable Water is 100% AND the Percent Reduction of Total Water is equal to or greater than 50%, WE Credit 1.2 is earned in addition to WE Credit 1.1.”

However, there is no mention in the Requirements section of WEc1.2 to reduce *total* water consumption by 50%. The last part of Requirement 1.2 talks about landscaping that doesn’t require any water after a year. The calculations don’t even mention this part of the 1.2 Requirements, and the 50% reduction in total water use is not a reflection of WE c1.1, since WE c1.1 is only dealing with *potable* water use.

Thoughts?

Thanks.

My 2 cents

Do they also give credit for “no” air-conditioning?

Local precipitation affects feasibility of collecting a sufficient volume of rainwater (if it doesn’t rain often, the system won’t collect enough water to reduce potable water use;

Local health (and building) codes in some states prohibit the use of harvested rainwater systems (so it’s important to check before including in design).

Supply water quality must meet standards established by manufacturers for specific fixtures (if quality is unacceptable, it could compromise long-term performance).

All of this is discussed in WEc2 “Regional Issues” on pg. 136 of the Reference Guide, 3rd edition.

a. Native vegetation
b. local precipitation levels throughout the year
c. local health codes
d. supply water quality

Ans: a.
Can anyone explain?

Drawings aren’t required, but calculations ARE required. ‘A’ doesn’t specifically mention calculations, but it is implied by saying “reduced by 100%”… ‘C’ is just giving a narrative, but no calculations.

Does that make sense?

a.Drawings and a narrative documenting and describing a captured rain system; irrigation use reduced by 100%.
b.Cut sheets for high-efficiency irrigation equipment and calculations demonstrating potable water consumption by occupants
c.A design narrative of the landscape design and a description of why a permanent landscape irrigation system is not required
d.A water budget calculation demonstrating that occupancy-based potable water consumption has been reduced by 30%

Answer given is a. I dont understand why the answer is not c (ie- no irrigation. I dont see anywhere that drawings are required for submission for this credit.) Any thoughts?

Which 3 might contribute to WEc1:Water Efficient Landscaping?

A. planting of hardwood trees to provide shade
B. use of native or adapted species
C. substitution of turf grass for other types of vegetation
D. reduction of total landscaped area
E. a combination of vegetated swales and rain capture

Correct Answers: A, B, E

Is C not a correct answer b/c it says “other types” and would only be correct if replaced w/ native/adapted species?

And for answer E, I understand the rain capture, but how does vegetated swales contribute. I don’t find anywhere in the manual where it talks about them under WEc1.

As an alternative to turf/high maintenance ‘grass’, you can consider using ‘xeriscape’ which I believe was in one of the practice questions. More on xeriscape, you can get a quick read by
ttp://home.howstuffworks.com/lawn-garden/professional-landscaping/alternative-methods/xeriscaping2.htm

Maybe you can employ hardscaping area to reduce the turf area (which may contribute less irrigation but may affect stormwater runoff), but with all the LEED credits you should consider both good & bad synergies anyways.

I hope this can jog some idea to your question.

Per LEED NC Reference Guide Third edition page 119, it states under “2. Practical turf areas” as recommended design approach.

Reason behind it (I think) is turf need to be constantly irrigated & maintained frequently (as compared to native/adaptive plants), has higher “Specie Factor (ks)” on page 121 & 122 table 1; thus contributing to more demand of irrigation water use.

The way the Controller Efficiency (CE) is determined for WEc1 calculations, is explained in the Ref. Guide NCv2.2 (3rd. Ed)pg 122. You basically get this info. from the weather-based controller mnfr. or landscape architect. This factor is not shown in the examples in the ref guide. In preparing for the exam, I looked at very technical info. in The engineering guide to LEED by
L. Haselbach where I found the answer to your question. Is unlikely that the questions on the exam are this technical.
Good Luck!

Ernesto Infante

If you are concerned about preparing for the exam, the exam won’t ask you to calculate that formula, nor will it ask you to regurgitate the .6233 “business.” Good luck.

Gary

Thanks,
Vernon

Thanks for answering that question. I passed the exam Friday, Nov. 21, and I’m happy to say that there were no questions about that. Ha!

Thanks,

Gary

options 1, 3 and 4 make sense to me in that they are in line with the reference guide (2.2, v.3), but option 2 seems to be an additional option, which in the current reference guide seems to have been rolled into option 3.

can anybody clarify? or have the templates been overhauled (and are only accessible if you have a live leed project)?

thanks.

Hope this explains it.

Gary

Cheers!