Confirm construction type

[JPotter04210]

I am trying to establish the correct constrution type for an existing building for purposes of renovation. It is about 100,000sf of one story metal building with the majority of the building used for storage of materials. None of the materials stored are explosive or even flamable. The ancillary areas include about 5,700sf of office, 900sf of truck services such as oil changing and washing, and obout 900sf of repackaging operations. The repackaging is adding water to a dry caustic powder and repackaging for sales and shipment.

The building is fully accessible (around the perimeter) and is fully sprinkled.

The building itself uses fire spray coated steel columns throughout. The steel roof beams, joists, and decking are merely painted. The exterior walls are all steel construction (except of course insulation) as well. The roof is about 23' above the floor.

Utilizing area increases allowed due to the fire supression as well as the accessibility increases I conclude it could be classified as type IA, IB, IIA, or IIIA construction. I see types IIB and IIIB as allowing 97,500sf and thus falling a bit short.

So, thus far are my conclusions correct?

As an aside, how can one tell, in existing construction, what the fire resistive rating is for steel columns with spray applied coating?

 

[zigmark]

Wow, lots of questions unanswered here. What codes govern your questions? When was the building constructed? Would it fit into any of the unlimitted area allowances for its' occupancy, see 2009 IBC 507? Call it S-1 of Type VB construction and it sounds like it works.

That said, you should go back to the AHJ and see what it was built as and why, hopefully they maintained those records on the building. Determining the ratings and materials used even shortly after the fact can be pretty challenging without having the documentation from the AHJ or building owner on the construction methods used.

ZIG

 

[Big Mac]

If the construction is all metal (i.e. no wood) it sounds like II-B or II-N depending on which code it was built under. However, if any portionof the construction is wood, it is likely V-B or V-N.

You stated that is was fully accessible all the way around, but you never said you had 60' minimum sideyards. Unless you have 60' sideyards on all sides and an NFPA13 sprinkler system, it is unlikely to work as an unlimited area building.

 

[Big Mac]

As to the issue of fire resistance rating of spray coated columns and beams, you would need information about the material applied and the thickness would then determine the fire-resistance rating.

 

[Builder Bob]

Unless the designer has the ability to identify the construction type, I generally place it as a type V-B construction - any material allowed by code. The proof of construction type is on the designer...........

 

[AegisFPE]

As an existing noncombustible building with spray-applied fireproofing, it would seem reasonable to proceed as if a Type II-A. We would expect structural fireproofing to have been applied to minimally achieve a 1-hour fire-resistance rating.

Therefore, the existing building was apparently approved as a protected noncombustible structure, which should be at least consistent with Type II-A construction. If you needed to get to a I-B or a I-A, then it would seem appropriate to have to justify the fire resistance rating of the structure.

 

[beach]

Does the building dept. have any permit or C/O history on the building?

 

[Builder Bob]

As an existing noncombustible building with spray-applied fireproofing, it would seem reasonable to proceed as if a Type II-A. We would expect structural fireproofing to have been applied to minimally achieve a 1-hour fire-resistance rating.Therefore, the existing building was apparently approved as a protected noncombustible structure, which should be at least consistent with Type II-A construction. If you needed to get to a I-B or a I-A, then it would seem appropriate to have to justify the fire resistance rating of the structure.

Unless the designer has the ability to identify the construction type............... The only drawback is what shape is the spray on in, is it the correct thickness, was it ever verified at time of installation, and what kind of hack job has remodels done to the insulation for the addition of clamps, supports, etc for the MEP's over the years.

Hence, unless the designer can identify the construction type.

a bat can look like a bird at twilight..... it isn't until you get closer or study the flight characteristics can you identify the flying object as a bat or a bird.

 

[Frank]

It sounds like what would now be 2A if constructed under the BOCA legacy code and the roof beams are over 20 ft above the floor there were provisions for all use groups to delete roof structure fireproofing.

Under some legacy codes the unlimited area building setback was 30 ft.

When was it built and where is it as to determine what code it was constructed under.

In most areas the adminstrative provisions allow continued use of a building withthe same use groups even if it does not meet current provisions--ie a building constructed under the old unlimited are provisions does not have to have the setback increased from 30 to 60 ft just because a new business moves in without significantly increasing the hazards.

The above advice to put in a records request with the AHJ is sound they may even have the plans available for inspection and copying.