Foam Plastic Insulations

Did you know that you can not leave rigid board, spray foam, and other types of plastic insulation uncovered?  I hope so... otherwise, go back and cover it up!  Do you know the reasoning that drives this code requirement? 

I spoke with a local code official in Lexington, Kentucky and he said it was to protect occupants and fire fighters from a number of things: 1) The increased burning rate and elevated surface flammability of building materials; 2) High density smoke development; 3) Molten dripping plastic from ceilings or walls; and 4) Seriously ugly “blue board” aesthetics. J

There are all types of plastic insulations, and I won’t bore you with all the highly technical names for them.  What I want to focus on are the code requirements when using plastic insulation such as open cell or closed cell spray foam insulation, and rigid insulation board.

Chapter 26 of the 2006 IBC is what we will be referencing throughout this article.  To begin with, IBC 2603.3 generally states that foam plastics shall have a flame spread index of not more than 75 and a smoke development index of not more than 450 (there are exceptions).  Most widely used foam insulations and rigid boards meet this requirement, but double checking never hurts.

IBC 2603.4 states that an approved thermal barrier of 0.5” gypsum board (or equivalent) shall be used to separate the interior of the building from the foam plastic material.  This thermal barrier is supposed to prevent temperature rise of the foam plastic material for 15 mins.  There are a number of exceptions listed under IBC 2603.4.1 to where it is not required, due to equivalent or better life safety “trade-offs”.  For instance, on EIFS exterior facades, the insulation board is limited to 4” thick unless you have special test data for the product, or if it is an insulated metal panel.  I would read up on this section if you are using foam plastic insulation inside or outside the building.

Now, what if you have a situation like mine: Denham-Blythe Co. Inc. and I were designing a two story dairy silo alcove building, where the inside of the first floor was air-conditioned at 40 degrees and the second floor was simply heated or cooled.  We used insulated metal panels for the exterior walls and they required a concrete floor above.  We had to find a way to insulate the underside of the deck to prevent energy-loss and condensation accumulation.  We could have used a metal panel ceiling but we needed access to the piping above.  We couldn’t use gypsum board because it is a wet environment, not to mention all surfaces had to be “food grade” materials.  Do any other ideas come to mind?

Well, closed cell spray foam insulation would be the best bet since it will act as a thermal and air barrier and will not support mold growth.  Slap a food grade drop ceiling in there and we’re good.  But what about this pesky thermal barrier the building code requires?  The drop ceiling cannot act as the thermal barrier…  Ah, here’s answer!

There are spray applied liquids that can act as the thermal barrier in specific tested assemblies.  Spray the foam, spray the liquid barrier, and you’re done; no other thermal barrier needed.  Below is an illustration of my situation:

We used Bayseal CC, Bayseal CC, and the thermal ignition barrier Flameseal TB on my project.  There were no issues with permitting; all we had to do was submit the ICC report to the plan reviewer and keep a copy on the jobsite for the building inspector.  After installation of the spray foam on the deck, we installed a stainless steel grid with gaskets and a washable “food grade” lay-in ceiling tile that was heavy enough to not pop out when sprayed down with water.  Success!

Now I am not plugging any products for my benefit, because I do not get paid for writing this blog, but I will mention a few here I found during my research: 

●     LD-C-50 open cell foam insulation covered with DC 315 is an ICC-ES approved assembly (ESR-1826).

●     Bayseal CC and Bayseal PP closed cell foam insulation covered with Flameseal TB is an ICC-ES approved assembly (ESR-2072)

Now for rigid board insulation applications, I also found:

●     Thermax White Finish insulation board is an ICC-ES approved assembly (NER-681)

●     Thermax Heavy Duty insulation board is an ICC-ES approved assembly (NER-681)

●     Styrofoam SIS (structurally insulated sheathing) is is an ICC-ES approved assembly (AC269)

●     Structurally Insulated Panels (SIP’s) that would be a great application for residential projects.  The ICC-ES approved assembly is ESR-2233.

Please check out more projects and helpful links for Architectural design, Web design, and Graphic design at www.apdesignsonline.com.  Please become a follower of this blog by clicking the “join this site” under the followers button on the right hand column.  Happy Constructing!

Stair Risers

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I just ran into an interesting situation recently. I had designed a set of exterior open grate metal stairs per the building code but the steel fabricator decided to construct them in another way. They will remain nameless to "do no harm". I received a phone call from the superintendent saying that the building inspector "dinged" us on these stairs during his inspection. So of course I asked if they were designed and installed per the architectural drawings. His response of course was "NO". What was missing? A simple piece of angle or bar stock should have been welded to the back side of the tread to prevent a 4" sphere from passing through the riser. The story ends with the fabricator resolving the issue on his own dime, unfortunately for them.

Most stairs are required to meet IBC provisions, except a choice few exceptions in an Industrial, Utilitarian, I-3, or other specified occupancies. Ships ladders and cage ladders are allowed in very specific circumstances, but must follow OSHA requirements.

The stairs in the above story were designed in accordance with 2006 IBC. The specific section that deals with stair risers is IBC 1009. If you read this section you'll notice there are different requirement for handicapped accessible stairs and non-handicapped accessible stairs, which I'll call "standard stairs".

Standard stairs require that a 4" sphere not pass through the riser per IBC section 1009.3.3 exception 1. In my opinion, this is a life safety provision- to prevent your foot from getting too far back on the tread and getting your toe caught on the tread above and having a less than thrilling spill. I have worked with a few stair detailers/fabricators that knew of the code provision, but did not follow it unless specifically asked to... and one who apparently didn't care to follow directions at all. This is rather alarming to me, so I try to do my best at checking shop drawings and communicating this code requirement clearly; I suggest the same to anyone else.

Handicapped accessible stairs require closed risers- no exceptions. What stairs have to be accessible? Due to length and content, I will cover that subject in a separate article entitled "Accessible Stairs". But be sure that YOU know, or else I see change orders in your future :)

So if a detailer/fabricator tells you that you don't need the angle or plate on the back of your stair tread (when you know it’s required) please educate them... It will improve both of your lives!

When is Safety Glazing required?

One code requirement that gets passed by all the time is the requirement of safety glazing.  When and where is it required?  First of all, reference your applicable version of the building code.  We will use the 2006 IBC for example.  Required locations are listed under "Hazardous Locations" IBC section 2406.3 (reference the link).  


Items #1, 6, 7, 10 & 11 are what I deal with on a regular basis; although, I find myself referring to # 6 & 7 more often.  The text in the code is a bit confusing to understand, so lets look at some illustrations:

Here are some helpful links which these illustrations originated from, but be warned... they are based on similar but different codes.  Be sure to use the version applicable to you!


Safety Glazing link 1

Safety Glazing link 2

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