Repair of sprayed-on fireproofing

[peebee]

I have a job where there were existing metal trusses with sprayed-on fireproofing. My electrical contractor come through and scraped off small areas of the fireproofing wherever he attached some new conduit supports.

Can anyone tell me what requirements (if any) for repair/replacement there are at each hanger location? I suspect there may be options for new sprayed-on or troweled-on firestopping, or perhaps a putty. Maybe do-nothing is OK.

Also, are there any specific requirements for the installer, or can my EC make the repair by himself?

 

[peebee]

Well, they got some muck and troweled it on. I have no idea what the muck is, hopefully it's listed for the purpose. Gotta be better than nothing.

I'm still interested to see if anyone has any thoughts on this. I thought this would be an easy question.

 

This sounds like a question for your fireproofing vendor, if you know whose product was used for the fireproofing. If it is intumescent (like Chartek or Pitt-Char), the remaining fireproofing may swell enough during a fire to cover over the conduit supports, but the vendor would have to evaluate this. Since the scraped places have been covered with "muck", I am guessing that your fireproofing is not intumescent but is cementitious--either plain old concrete or some proprietary lightweight fireproofing like Fendolite or Monokote PK-150. If the "muck" is also cementitious, you're probably OK, but, again, your best source of information would be the original fireproofing vendor--or ANY reputable fireproofing vendor, for that matter.

 

[humanfactoreng123]

http://www.comm-2000.com/productdet...s&ProductID=UL1709_2_S_19940215(ULStandards2)

Standard for Rapid Rise Fire Materials for
Structural Steel

JOHN HEYWOOD, P.E., CSP
SENIOR SAFETY ENGINEER
Saint Louis, Missouri 63125

 

[RegisPreact]

Additionally,
A. MATCH. It is important that the "same" system be included and not mixed. In fact, even manufacturers/vendors with similar products do not allow their own products mix and match such as the 2 part epoxy Thermo-Lag to correct the 1 component Firesorb or vice-versa. Remember that these are tested assemblies and as a rule tested assemblies do not usually have mixed systems.
B. PRECISION. On certain assemblies where there is a required fabric, you should inspect that damaged component and apply the same required combination of fabric, top coats, etc.
C. INSPECTION IS KEY. From experience I have been asked to patch monokote but upon closer inspection noticed the delamination process on bigger areas of the Q Deck/fluted metal decking. Adding even more weight to material already separating would have had bigger chunks fall off, and I walked on that repair because they didn't want to do proper patching repair. Instead they found some lesser cost inadequate entity to do this. The opening day showed particles all over the nice new crimson red carpet.
D. AVERAGES. There is a statistic in the industry and in some product manufacturers' books that 80 to 90% of the coated areas had to be perfect or average out to the "minimum required thickness".
E. INTEGRITY. Reputable providers of solutions offer proof of thickness of coatings by their applicators, and if you are in this for the long haul, there are some scientific devices on the market you can acquire that will help you do your own inspection of thickness. In my area of NYC where there are many tall buildings the inspectors are notorious for only inspecting the first one or two floors and not going any higher. Thus, the dishonest applicators pocket the difference of what they were paid for and what they didn't apply.