# S-1 Aircraft Hangar Fire Barrier



## retire09 (Oct 29, 2012)

I have a plan for an 8,800sf S-1 aircraft hangar with an additional 5850sf of office area.

No occupancy separation is required between the S-1 and the B but with no fire separation they have a single fire area of 14,650sf containing an S-1 occupancy.

Is this not required to be reduced to less than 12,000sf in the combined fire area or fully spinklered?

I think so but if it does, what rating of fire barrier is required to reduce the size of the fire area?


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## steveray (Oct 29, 2012)

706.3.7 fire-resistance rating requirements for fire barrier assemblies between fire areas

f-1, h-3, s-1

 3


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## retire09 (Oct 29, 2012)

If they change the use to an S-2 Hangar, can they get by with a one hour occupancy separation instead of the 3 hour?


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## steveray (Oct 29, 2012)

A, b, e, f-2, h-4, h-5,

i, m, r, s-2

 2 hrs


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## AegisFPE (Oct 29, 2012)

See IBC Section 412.4.6!!!

There are special provisions for aircraft hangars.

Fire protection may still be required per NFPA 409, which cannot be answered by what you have posted because it depends on the construction type.


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## retire09 (Oct 29, 2012)

This is type III construction and a group III hangar.

Would IBC 706.3.8 allow a 1 hour separation if the occupancy was changed to S-2?


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## cda (Oct 29, 2012)

AegisFPE said:
			
		

> See IBC Section 412.4.6!!! There are special provisions for aircraft hangars.
> 
> Fire protection may still be required per NFPA 409, which cannot be answered by what you have posted because it depends on the construction type.


ding ding ding, we have a winner!!!!!!!!!    know the code before typing a response, I gues I should follow that creed


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## retire09 (Oct 29, 2012)

I think I may have found the answer to my own question with 901.7.

It sounds like you have to provide a fire barrier in accordance with 706.3.9 (3hr for S-1 and 2hr for S-2) if you are trying to avoid sprinklers. So the 1hr occupancy separation is not an option beween an S-2 and a B?


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## TJacobs (Oct 29, 2012)

retire09 said:
			
		

> I think I may have found the answer to my own question with 901.7.It sounds like you have to provide a fire barrier in accordance with 706.3.9 (3hr for S-1 and 2hr for S-2) if you are trying to avoid sprinklers. So the 1hr occupancy separation is not an option beween an S-2 and a B?


Correct...2 hours required.


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## cda (Oct 29, 2012)

Have you looked at Ibc 412 and Nfpa 409


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## mtlogcabin (Oct 29, 2012)

An aircraft hanger is an S-1

311.2 Moderate-hazard storage, Group S-1.

Buildings occupied for storage uses that are not classified as Group S-2, including, but not limited to, storage of the following:

Aerosols, Levels 2 and 3

Aircraft hangar (storage and repair)

TABLE 707.3.9

FIRE-RESISTANCE RATING REQUIREMENTS FOR FIRE BARRIER ASSEMBLIES OR HORIZONTAL ASSEMBLIES BETWEEN FIRE AREAS

The S-1 requires 3 hours

The B requires 2 hours

The most restrictive applies

A 3 hour fire barrier is required to seperate the uses into 2 fire areas 

Can you up the building to Type III A  construction as referenced in Table 412.4.6 and increase the fire area to 15,000 sq ft?


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## retire09 (Oct 29, 2012)

311.3 Low Hazard storage, Group S-2 first on the list is Aircraft Hangar.

The only difference is repair and as long as it remains a group III hangar by NFPA 409 I don't know that it matters if they call it a S-1 or S-2.


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## mtlogcabin (Oct 30, 2012)

> 311.3 Low Hazard storage, Group S-2 first on the list is Aircraft Hangar


You are correct under the 2006 IBC Aircraft repair hanger is S-1 and Aircraft Hanger is S-2

In the 2009 IBC Aircraft Hanger was moved to an S-1 and storage and repair are grouped together.

So under the 2006 a 2 hour fire area separation between the S-2 aircraft storage and the B use

Under the 2009 a 3 hour fire area separation between the S-1 aircraft storage and the B use

Got to love those code changes:banghd


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## retire09 (Oct 30, 2012)

If they did go to the III-A construction would they still have to provide sprinklers for the S-1 at 12,000sf per 903.2.9 or would table 412.4.6 allow the 15,000sf fire area without sprinklers.

Looks like a conflicting standard.


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## mtlogcabin (Oct 30, 2012)

I believe Table 412.4.6 is applicable because it is specific to airplane hangers where as 903.2.9 is general to S-1 occupanies

102.1 General.

Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall be applicable


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## sdpaddler50 (Oct 30, 2012)

One aspect you may want to verify, is whether the planes have fuel in their tanks when inside the hangers. I have not been involved with hangers for a long time, but if I remember correctly, SOP is to only allow a min amount when inside. AS others have noted 409 is where the meat is in regards to this occupancy. The big foam/deluge systems and water cannons for the large carriers are amazing.


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## Glennman CBO (Nov 2, 2012)

The "specific and general" references to the code apply only to the adopted code. The referenced standard only applies to the extent that it is referenced by the adopted code. Unless NFPA 409 is adopted in it's entirety, it is only to be used to determine groups (group I, II, III) for the purpose of fire protection. Then you leave the rest alone, and return to the code for all other items.


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## sdpaddler50 (Nov 2, 2012)

Specifying, and designing fire protection systems with only the fire and bldg. code would not be possible for a large, commercial grade hanger. The code does not provide the specifics needed. Any large hanger using sophisticated foam water deluge systems that are activated by heat detectors along with water cannons for under wing areas, etc were designed with NFPA 409, along with NFPA 13, and other NFPA standards.  This is the case for any large airport where hangers are involved.


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