Tag Archives: tornado shelter peer review

Should I be designing my storm shelter per the ICC-500 or the FEMA P-361?

Recently we have had a couple clients ask about community storm shelter peer reviews and why we are peer reviewing the designs per the ICC-500 and not the FEMA P-361?  The simplest answer is the ICC-500 is a standard that is tied directly to the building code and the FEMA P-361 is a guideline.  The ICC-500 must be followed if you are designing a storm shelter using the IBC 2009 or later.  The FEMA P-361 guidelines may also be required if the storm shelter is funded by a FEMA grant.

The next question we are often asked is if there are discrepancies between the two documents? That question can be answered by the FEMA P-361 Appendix D which is a “Comparison Matrix of Differences between ICC 500 Requirements and FEMA Recommended Criteria.”  As you can see by the provided matrix the main differences are in regards to coastal flooding shelters and first aid kits.

Thanks for following, and remember.  Ask questions, do your research, and make an informed decision. The lives of you or others may depend on it.

Written by Shauna Schultz, AIA

Using Toilets for Tornado Shelter Space

Sanitation facilities are required for community tornado shelters.  After conducting several peer reviews over the past few months, I am seeing this trend in using required toilets as shelter space.  To clarify, these restrooms have been single fixture restrooms intended to be utilized by one person at a time.  That is ONE, not 10 or 11!  Some designers are including these required restrooms in the shelter’s overall occupant load count.

Let’s consider an example.  I have a 450 sf (gross) training room with (2) single fixture restrooms, each about 85 sf (gross) both of which are required by code to support the shelter occupants. The following would be the proper calculation for the occupant load:

  • Training Room – 450 x 65% Reduction Factor ÷ 5 sf/occupant = 58
  • Restrooms – 2 rooms x 0 occupants = 0
  • Total Occupant Load of the Shelter = 58

Here, the restrooms are designed for the use of occupants that are in the training room.  This is the most conservative approach.  One could include ONE occupant in each restroom on top of the 58 in the training thus a total of 60 occupants.  The thought is a one for one trade from the training room to restrooms as individuals need to use the restroom.

Now here is a calculation that I see as a trend:

  • Training Room – 450 x 65% Reduction Factor ÷ 5 sf/occupant = 58
  • Restrooms – 2 x 85 x 65% Reduction Factor ÷ 5 sf/occupant rooms = 22
  • Total Occupant Load of the Shelter = 80

First of all, the reduction factor should be 50% for a restroom so it is a problem right from the get go.  The fixtures and door swing take up a lot of the restroom space.  So what happens when two people have to use the restroom?  Two occupants go in, 22 come out.  A net of 20 additional occupants now in the Training Room.  THE TRAINING ROOM IS NOW TOO SMALL!!!!  It just doesn’t work!   If you need 80 occupants, then size the Training Room for a minimum of 78 or 80.  If you have additional restrooms that are over and above the minimum, then one could consider loading it up with occupants; people that don’t mind standing in restroom with 7-8 (based on the example with a 50% reduction factor) what could be perfect strangers for 2 hours or more.  That wouldn’t be for me!

I think this trend is to justify more occupants than necessary to justify more space that is funded by a government agency.  In other words getting space paid for by that government agency that will never be used as shelter space.  Here’s the sad part; those funds provided by government agencies are fixed and those “pots of gold” as some refer to it do run out.  So therefore, when a building owner with the help of a designer takes more grant money than what they need, then another group, maybe kids in a school may not get a shelter because the funds have dried up.  In the end, it could cost that particular designer another shelter project to boot!

It’s that simple!

 

Be careful out there!

Written by Corey Schultz, AIA, LEED BD+C