Walk Off Mats and Grates - In or Out?

Short Answer: Inside Medium Answer: Inside the building, but it can be outside if it's "protected from the weather" Long, Rambling Answer in Story Form Including a Few Rants: We were working on a high end project and I brought up the fact that we need walk-off grates at all entrances that are at least six feet in the main direction of travel. Sounds simple enough but then there was a question: "Do the grates need to be inside or outside the door?" Since the point is to keep dirt and debris from entering the building, I came to the logical conclusion that the grates we need to be on the outside. The credit itself calls you to "Employ permanent entryway systems... to capture dirt and particulates from entering the building at entryways that are directly connected to the outdoors." If you've placed a grate or grill inside the building you've already lost the battle right?

Obligitory Post Picture Alert

Yep, that's a grate

By having it outside the door, the grates allow dirt to drop to the bottom, and when it rains some of the dirt could be washed away. Also, people will be stomping their feet, a process that is certain to kick up dust indoors. I was pretty certain, but I wasn't 100% sure so I decided to check the reference guide.

Why I'm Annoyed with Flexibility Those of you used to searching for practical, detailed information within the reference guide can probably guess where this is heading... The reference guide frequently stops at the level of giving practical advice like this. I understand the reasoning. By keeping things vague you allow for unforseen circumstances to be dealt with in a case by case basis. In theory it allows costs to be controlled, but in practice it's annoying. On the plus side, at least I have stuff to blog about. Credit Interpretation Requests (aka CI Rulings) If you haven't been initiated yet, the place where the answers are is within the CIRs... This is your answer depot. Luckily, someone else had the same question (note: you must work for a USGBC member company or be listed as a team member on a LEED registered project to havea access to the preceding link) and submitted it for a CIR. In fact two people did within eight days of each other... Scroll down to the ruling on 11/01/2004: "The intent of EQc5 is to prevent contaminants from entering the building which could have an effect on the indoor air quality. However, the location of the 'permanent entryway system', for example grills and grates, is subjective, depending on the layout of the building. If there is a vestibule it may be appropriate to have a walk off area located within it. Also, exterior walk-off areas may be considered if the area is protected from weather. Alternatively, the walk-off area can be within the building." How's that for a definitive answer??? My interpretation of this interpretation is that you always go inside unless you have a covered area (i.e. rain can't get on it). As we're largely talking about metal grates and grills, I don't buy the argument that they could "get wet and muddy", but c'est la vie.

Grate and Grill Manufacturers

BuildingGreenSuite review: I love you

It's going to be rare that you see me hawk services for other people, though I'm not necessarily opposed to selling out (if the price is right). If I do you'll probably be able to tell by the giant ads on the side of the page. I want to assure you that I've recieved no money for the advice I'm about to offer.

BuildingGreen Suite

For an architect, contractor, or LEED consultant spending a decent amount of time tracking down sustainable materials and products, you MUST check out the GreenSpec directory and Environmental Building News. The former offers the most comprehensive directory of sustainable products and materials I've seen, and the latter offers the most concise, accurate, and most importantly independent, reviews of various sustainable products and industries.


I suggest not subscribing to either independently but rather going ahead and chunking up the $199/year subscription fee for the whole deal. If I remember correctly there's a pretty substantial discount for AIA members, but I'm not sure what that is. Oh, and don't mess around with the paper versions, there are frequent updates online that you need access to.

Honestly, if you're only working on about 1 LEED or sustainable project a year, you can probably get by with what you can find for free, but if you're working on multiple LEED projects at once this is the deal of the century.

Project Database

The suite also gets you access to a thorough database of sustainable projects (often including much sought after financial info), though this is really only an extended version of a freely available database run by the US Dept. of Energy. As of today, the free DOE site has 98 projects while the subscription BG database has 98 LEED and 206 total projects.

GreenSpec Directory

The single greatest aspect of this directory is searchability (spell check says that's a word so I'm going with it). I can view products by LEED credit, and further cross reference them by CSI division. If I browse for "Urinals", I can find a list of ultra-low flow and waterless manufacturers, but the page will also be cross-referenced with articles about the industry in general (in this instance, a great piece on problems with waterless urinals and how to avoid them - the problems, not the urinals). If a contractor sends me some crap submittal about not being able to find low-VOC paint or bamboo flooring, this is where I'll go to prove them wrong. The time savings of finding three sources for a competitive bid in one place is a huge help on public projects as well. I use this site at least 2-3 times a week.

Environmental Building News

I'm a researcher at an architectural firm, and that often means writing reports about various materials and systems. EBN frequently does my job for me, which is probably why I love it so much. The articles are very thorough and always include perspectives from engineers, architects, and the various manufacturers involved. They can be techinical (read: boring, likely as many of my posts), but are always clearly written and easy to understand. My thought is that if you need to know something, you're probably going to have to do some boring reading at some point... I'm on this site at least once a week.


My only real complaint about the directory is that it stops short of providing hard data. The site will tell you that the carpet has recycled content, but not how much... you're left on your own to slog through the mfr's site for that. I can understand the reasons (these numbers are always changing), but it's still frustrating that there is not a single source for that kind of information.

Other Options

  • 4spec.com - Not good for stuff like recycled content, but this more typical construction materials directory has an option of searching by mfr zip code (and CSI designation of course) that works surprisingly well for determining regional content.
  • SC Green Building Directory - For those lucky enough to live in (or to a lesser extent, those within 500 miles of) South Carolina will soon have a locally focused green building product and services directory run via the SC Sustainability Institute. Right now they're accepting submissions of product and services and the actual directory is offline. I'll update on progress as it develops.
  • Google - A little annoying to use, but at the end of the day it's free and will get the job done.

Did I miss a good info source? Leave a comment below!

Certifying Multiple LEED Buildings Together? Part 1

I've been working on two large LEED projects that each contain multiple buildings. On one we decided to certify each building independently, on the other we're working on certifying a group of buildings under a single certification. In theory, the MPAG should be able to save us money (on certifications) and time (which is money), but in practice all it's done for us is help us to lose points.

Part 2 Now Avalable!

View the "LEED-NC Application Guide for Multiple Buildings and On-Campus Building Projects (AGMBC)".

The Money

The best argument for certifying buildings as a group is for saving on certifacation fees, but this doesn't work in every scenario. While there is the potential for reducing certification fees, it will only happen if you (A) have multiple buildings under 50,000 sf or (B) multiple buildings over 50,000 sf that total more than 500,000 sf.

The reason for this is the way certification fees are charged, which is a flat rate/sf. There are minimum charges for buildings 25,000 sf or less (hence situation A) and a maximum charge for buildings 500,000 sf or over (hence situation B). Take a look at the rate sheet and we'll run through some examples...

Many Small Buildings Example

Let's say I have five 15,000 sf buildings. If I'm certifying them independently, I'll be paying 5 registration fees ($450 each) and five fees for buildings less than 50,000 sf ($1,750 each) for a total of $11,000. If I combine the certifications, I effectively have a single building of 75,000 sf, yielding a total registration and certification charge of $3,075, or a savings of about $8,000. Not bad, especially on a smaller scale project.

Many Mid-Size Buildings Example

What if we had 5 buildings of 75,000 sf each? Registering separately at $3,075 a piece, we have a total charge of $15,375. Registering the projects together we effectively have a single building of 375,000 sf. Since this is within the 50,000 - 500,000 sf range, we're really only saving the flat registration fee, and our total cost of certification becomes $13,575, or a savings of $1,800. Doesn't hurt, but in the context of a 375,000 sf of floor space this really isn't much.

Many Really Big Buildings

This is where you really can make some savings. Now lets say we have five 375,000 sf buildings. Registering separately at $13,575 each, we have a total cost of $67,875. Since there is a maximum charge of $22,500 for buildings over 500,000sf, we're effectively saving certification fees on 1.375 million sf of space, or $44,925!

Now that you took the time to read through all of that, take a look at the much easier to read chart!

LEED Multiple Buildings Registration Fees

Rounding up or down?

If you're looking at preferred parking (SSc4.3) for and you determine that your project needs 4.15 LEV parking spaces, how many should you provide, 4 or 5? While this is a relatively harmless difference (one more sign probably won't break the bank), the difference between 1 or 2 showers (SSc4.2) might be more of an issue in an small office building.
I wasn't sure about this answer until I noticed that the credit templates solved the answer for me. One tenth of a shower is a full shower, and rounding up, even when the numbers would typically be rounded down is the norm.
Take the following example:
5% of 180 FTE is 9.00000 secure bicycle storage spaces require. If we add one more FTE, then 5% of 181 is 9.05, which in most minds would round down to 9. In this case however, the LEED credit calculator rounds the number up to 10 required spaces:

Determining Occupancy

So we need to know our occupancy for our nice LEED project... great. This question bothered me for a long time, especially since it affects so many credits. Then I realized you're basically supposed to make it up! Really though, the owner is supposed to supply you with the numbers, but how is he going to do that if they're not sure? If you're working a core and shell project that fits neatly into the groupings below, you can use the default occupancy numbers (in square feet/FTE) below. Most credits is defined as SSc4.2, SSc4.3, SSc4.4, EAc1, EQp1, EQc1, EQc2, EQc6, and who could forget, EQc7. See the LEED-CS reference guide (page 441) for more detail.

Core and Shell Default Occupancy Counts

If you're not fitted nicely into one of those groups, you're on your own. I take the code occupancy count and break out the reasonably inferred FTE. If you have a restaurant, there are only going to be so many cooks in the kitchen, tables per waiter, a hostess, a bartender, and a manager. I would then subtract that number from the code occupancy to give me the transient loading, which would be added to the FTE number to determine peak loading. In a mixed-use project you would need to look at hours of operation - as peak loading for a movie theater is likely to be on a different schedule than peak loading for an office. See below for an example breakdown for SSc4.2, Bicycle Storage and Changing Rooms.

Am I wrong in my assumptions? TELL ME! Please use the comments to make this site more informative!

Por que, Brutae?

Hi. I'm Joel. I'm a LEED AP. The first thing I learned when after I earned my LEED accreditation is how much I still didn't know. There's plenty of information out there on how to design sustainably, but precious little info on how to get your documentation done. Sure, I know I need to know the full time equivalent occupancy for my restaurant and also the peak loading, but how the hell do I get those numbers? This blog is an attempt to fill that void. I've previously posted questions on the 4specs.com discussion forum (highly recommended), the designcommunity.com "LEED and Green Certification Forum" (less helpful but still worth the time), and the USGBC's own Member to Member exchange (a surprising waste of time, though it looks like it's getting more use these days). The first few posts in this blog will likely be familiar to those who frequent these forums. I've taught LEED AP classes at our firm and with local EGB groups, and also given presentations on managing LEED documentation and materials selection. In no way would I ever claim that I'm an expert, but I feel like I can help with some of the problems I've encountered in the past. Please use the comment features to add your experience, call me an idiot, etc. I'm not a consultant, and so please don't try to hire me! I'm very happy with my current job as a researcher at a great architecture firm, and don't plan on leaving any time soon. I just want to provide a forum for those of us tasked with actually certifying buildings to get things done.