Showing posts with label question. Show all posts
Showing posts with label question. Show all posts

Wednesday, April 21, 2010

LEED Certification, When Is It Worth It?

Question from LinkedIn:
LEED per square foot: When is it worth it?

Nathan's Rather Lengthy Response:
We've started to pursue LEED certification for a lot of our smaller commercial interior projects (and all of our big full gut renovations or new construction projects). Once the contractors / designers have worked on a few projects, we've found no soft cost premium (and since we always put the LEED requirement in the RFP, only people who already know or are willing to learn on their dime will respond competitively). For those few firms who say LEED will be a big up charge, we ask why specifically. We will get ridiculous reasons like "to do the ventilation rate calculations", "to track C&D waste diversion", or "to do line of sight geometries." The obvious response is to ask how they were planning on sizing ventilation loads, confirming they were meeting our 95% C&D waste diversion requirement, or verifying the percentage of occupants who could see a window. Since these things are important to us, we have them as requirements in our contracts and construction documents. Since they're important to us, we expect teams to provide verification that they're meeting our requirements. Since they're preparing the verification anyway, there is almost no extra work to go for LEED. Since we are able to collect all of the LEED documentation and compare past projects to future projects, we're able to ensure that our buildings are getting better and better over time (making sure the learning that comes from a project stays with us rather than leaving with the project team). We have seen a tremendous benefit from commissioning but some reluctance on smaller projects, so we now offer an in-house commissioning service for these projects (we've seen amazing benefits even when only commissioning light controls and bathroom fixtures). We don't consider this an added cost of LEED, again because the benefits are so obvious all projects should be doing this, LEED or not. So on a small (say $500,000 classroom fit-out) project, the extra $3,000 seems well worth it to us.

Hard cost premiums are always optional and we evaluate those on a case by case basis in light of benefit to the project versus additional cost (LEED points being only a secondary concern). Added cost for MDF w/o urea formaldehyde? Yes, but the few buildings we've used urea formaldehyde MDF we've gone in, conducted IAQ tests, and can see elevated levels of formaldehyde in the space. Let's go with no urea formaldehyde (our standard). PV on the roof? Payback is generally more than 20 years (as a non-profit we don't get tax credits - this all changes with a PPA). We have other projects we can spend the money on with much better payback / environmental benefit. We typically don't go with PV. FSC wood is case by case. Improved HVAC equipment is usually a yes and we try to minimize additional cost by pursuing utility incentives and using integrated design to right-size everything / realize the interactions between systems.

I completely agree when you're doing most of the work yourself and you’re really passionate you can hold yourself accountable. My brother and I built his house recently and we held ourselves accountable (he did most of the work, but I helped on occasion and with equipment selection). The couple of thousand dollars extra for LEED for Homes was more than he wanted to spend (house cost $350 K). Though the house is beautiful and efficient, as money and time ran short, there are all sorts of minor corners that he or his subs ended up cutting that collecting documentation (which is VERY minimal in LEED for Homes) would have helped address. Admittedly, he's not really passionate about the environment (we was more concerned about utility bills), but imagine what happens as soon as you have somebody else doing your construction with little direct oversight from the owner. Without documentation many environmental claims can't really be trusted and history has proven this over and over again. On a side note, in his market (SW Michigan) he asked the appraiser about the ground source heat pump (what I think is meant by geothermal above) and was told they give no additional value for that system, though a propane tank does add to the home’s value. We went with the GSHP anyway, but only because the cost came in competitive with propane furnace. We didn’t go with the highest efficiency heat pumps because there was no way the system would pay for itself within its life span (we picked a mid-level unit – much of the winter heating is provided by a wood burning stove). How tight was the envelope when we were done? We don’t know because we didn’t do a blower door test. I’m sure he’ll continue to tell people it is tight though because he built it and he meant it to be tight.

Regarding the statement about LEED focusing on design rather than verification, of course this is why there is a LEED for Existing Buildings Operations and Maintenance rating system. All of the same arguments about certification apply. Of course you don’t need LEED to have a high performing building, but to be a good building manager you need to have an energy management strategy and track your utility bills on a monthly basis. You need to have a preventative maintenance plan and keep it up to date. You need to have staff training plans. You need to regularly do energy audits. Etc. If you are doing all of this, then LEED is very easy and has little cost. In all projects I’ve been on (more than 100 LEED projects), the teams that found LEED to be a lot of work were the ones that weren’t actually designing / building / operating in a sustainable manner and creating the documentation seemed hard because it forced them to actually go back and create documents that should have been created from the beginning if they were serious about sustainability.

Just my thoughts, not necessarily shared by Harvard, the USGBC, or anybody else with whom I'm affiliated.

Friday, October 9, 2009

Water Savings Calculations


Question sent by email:

I've heard you say you can save 40% of domestic water without any added cost. How do you do this? Is it use of gray water for flushing in addition to waterless urinals, low flow toilets, aerators on sinks, etc???

Response:

It was very easy to do in the past with fixture selection. The water efficient fixtures we use have no added cost compared to conventional fixtures. We could save a tiny bit more with gravity fed toilets (the kind with the tank like you have at home), but we usually use flushometer toilets (the more commercial kind with the silver pipes sticking out of the wall).

Lets look at the calculations assuming there are two people in the building, one man and one woman.

Base Case (code compliant)

Toilet = 1.6 gpf - 3 times/day for woman, 1 time for man

Urinal = 1.0 gpf - 0 times/day for woman, 2 times for man

Sink = 2.5 gpm @ 80 psi - 3 times/day for 25 seconds for everybody

Shower = 2.5 gpm @ 80 psi - 1 times/day for 5 minutes for 10% of people

Design Case (what we do)

Toilet = 1.6 / 1.1 gpf dual flush - 1 full 2 half times/day for woman, 1 full for man

Urinal = 0 gpf - 0 times/day for woman, 2 times for man

Sink = 0.5 gpm @ 80 psi - 3 times/day for 20 seconds (sensors) for everybody

Shower = 1.6 gpm @ 80 psi - 1 time/day for 5 minutes for 10% of people

The scenario above would save 48.1% of the water in an office setting based on a comparison to EPAct 1992 (calculation for LEED NC v2.2):

Now we usually get a little less credit for the same water usage because the base case for commercial sinks has been reduced to 0.5 gpm @ 60 psi.

Base Case (code compliant)

Toilet = 1.6 gpf - 3 times/day for woman, 1 time for man

Urinal = 1.0 gpf - 0 times/day for woman, 2 times for man

Sink = 0.5 gpm @ 60 psi - 3 times/day for 25 seconds for everybody

Shower = 2.5 gpm @ 80 psi - 1 times/day for 5 minutes for 10% of people

Design Case (what we do)

Toilet = 1.6 / 1.1 gpf dual flush - 1 full 2 half times/day for woman, 1 full for man

Urinal = 0 gpf - 0 times/day for woman, 2 times for man

Sink = 0.5 gpm @ 80 psi - 3 times/day for 20 seconds (sensors) for everybody

Shower = 1.6 gpm @ 80 psi - 1 time/day for 5 minutes for 10% of people

The scenario above would save 34.8% of the water in an office setting based on a comparison to EPAct 1992 and the new commercial fixture rules (calculation for LEED 2009). Of course there is no kitchen sink in this example (assuming a college dorm), but that would have to be added in if appropriate:


Residential buildings code still allows 2.5 gpm sinks, so we typically save 38.1% in old and new versions of LEED.

Base Case (code compliant)

Toilet = 1.6 gpf - 5 flushes/day for all

Sink = 0.5 gpm @ 60 psi - 5 times/day for 25 seconds

Shower = 2.5 gpm @ 80 psi - 1 time/day for 5 minutes

Design Case (what we do)

Toilet = 1.6 / 1.1 gpf dual flush - 1 full & 4 half flushes/day for all

Sink = 0.5 gpm @ 80 psi - 5 times/day for 25 seconds

Shower = 1.6 gpm @ 80 psi - 1 times/day for 5 minutes

Of course the calculations above are done for 2 people, but the percent reduction will remain the same regardless of the number of people as long as you assume a 50/50 split between men and women.

We have plans to use greywater in some buildings and one of my projects in South Carolina did th
is (see Half Moon Outfitters case study). Showers really drive the numbers in residential buildings and it is possible to go below 1.6 gpm. We usually use Delta H20 Kinetic showers, but many of the best low-flow showers aren't allowed in Massachusetts because they're not on the approved plumbing list. The toilet in the top right is a tank-type dual flush from Dubai. The urinal on the bottom left uses no water for flushing and has a trap that can be cleaned and refilled with oil (Kohler Steward).

Hope this helps.


Friday, July 10, 2009

BCA Commissioning Requirements

Posting on BCA Group at LinkedIn: There has been a lot of discussion about the BCA's certification being too difficult to obtain. The Certification comittee is looking for ways to make the certification easier to obtain without sacrificing the integrity of the certification. Ideas?

Response: As someone who has worked with a lot of bad commissioning authorities, I think the BCA certification requirements are great. How many projects have a commissioning authority sign off despite never having an OPR or BOD? How many CxA's use the nominal group technique to facilitate development of the OPR? How many CxA's use Guideline 4 to prepare the systems manual? CxA's that confirm As-Builts are As-Built? CxA's that suggest envelope commissioning in a complex building? I think the BCA and U of Wisconsin certifications give educated owners a level of confidence in their consultants and help give the industry a better image. I've worked on lots of clients who feel (after paying for bad commissioning) that it was a worthless investment though I'm convinced and the data supports that good commissioning is the smartest investment an owner can make. Nathan

Thursday, July 9, 2009

"Advertising" Green Buildings

Question: I work for the Office of Sustainability at ### University. I was wondering if you could direct me to the individual in your office who would know about green building done at Harvard. Specifically, I'm interested to know if any of the Harvard's green buildings have innovative ways of advertising their innovations.

Response:

We have a pretty big campus and over 60 green building / LEED projects and each advertises their innovation a little differently. We have real time utility displays in some:

http://buildingdashboard.com/clients/harvard/byerly/

http://buildingdashboard.com/clients/harvard/cowperthwaite/

http://buildingdashboard.com/clients/harvard/10akron/

All completed projects get case studies (eventually):

http://www.green.harvard.edu/theresource/case-studies/

We put the technologies used in an online database:

http://www.green.harvard.edu/theresource/tech-prod/

And a lot of projects have comprehensive signage programs, lab hood CFM displays, tours that are publicly available, etc. We usually try to write an article about new projects for our website:

http://www.green.harvard.edu/node/35

We then try to link to this site on the AASHE bulletin.

http://www.aashe.org/publications/bulletin.php

A couple of years ago we published a map of all our green building projects in the Harvard Gazette (click on the image on the bottom right):

http://www.news.harvard.edu/multimedia/specials/green/index.html

Hope this helps,

Nathan

Saturday, May 9, 2009

Energy Simulation Consultants?

Question from LinkedIn LEED AP Group: Where can I find a consulting firm that specializes in Energy Simulations?
Response from SustainableDCS: Almost any MEP can give you an energy model usable for EAc1 (most already use Trace or HAP to do their load sizing, both of which are acceptable for this simulation). Most will complete the model at the end of design to tell you how many LEED points you'll get. This is the least expensive option, but offers no real value to the design process. A good modeling firm will provide multiple parametric runs to help identify the best orientation, envelope, HVAC, etc. Some will also provid CFD analysis for natural or hybrid ventilation (or fume hood containment and avoiding exhaust plume reintrainment), daylight simulation, or radiant temperature simulation, depending on your needs. Transolar is the best we've used for the fancy stuff ( http://www.transsolar.com/ ). We really like Andelman and Lelek for eQuest models ( http://www.andelmanlelek.com/ ).

Friday, January 30, 2009

Integrated Design Question

From "LEED Accredited Professional" group on LinkedIn:

Wondering how to conduct an integrated design for a public project that must be bid out? How does one get contractors involved in the process? Anyone with experience on this? - Heather McGuire

This issue comes up in any traditional design-bid-build job (public or private). How do you have an "integrated" design when one of the key parties is not at the table? Similar issue if you're trying for integrated design in a speculative building when you don't have an operator or a tennant identified. I don't think there is an easy / one-size-fits-all answer, but you need to find a proxy for the missing party. If you don't have a GC on board, you can hire a Construction Manager as advisor during the design process and he or she can represent the contractor. Even if you can't go with a CM, lots of public bid jobs let you hire a Cost Estimator who could serve the purpose (a good Estimator can also talk about constructability). If no CM or Estimator is on board, the Project Manager could wear this hat. As a last resort, the Architect and Engineers can get preliminary costs for the various design options by calling vendors and sub-contractors. You might also invite a number of GC's to the design charettes with no promise of future work, but a definite advantage when it comes time to bid.

On a somewhat related note, it might be helpful to follow a formal Integrated Design process (something like ANSI WSIP - include as a contract requirement of all consultants) and use Life Cycle Costing to evaluate your different design options. For LCC, it is easier if you look at your costs using UniFormat (arranged by system) instead of MasterFormat (arranged by material) to really identify the trade-offs. You might also want to bring in your Commissioning Authority early (conceptual or schematic design) and have him/her participate in the charette process. This way the CxA can help pull together the Owner's Project Requirements early in design so the design team can refer to them in each of their design submittals. - Nathan