Airport hangars, lease line vs lot line

[Jon Victor]

IBC section 412.3.1 says that Exterior walls located less than 30 feet from lot lines or a public way shall have a fire-resistance rating of not less than 2 hours. Our jurisdiction has decided that a lease line and a lot line are the same and we will require all hangars to be 30' from the lease/lot line or build a 2 hr. exterior wall. The heartburn that I have is the definition is for a "lot line" and not a lease line. I have searched through several airports, SLC being one of them, and they only require 10' from the assumed property line between the two buildings as per IBC table 602.
Has any of your jurisdictions created a policy for hangars and if so, would you please share that for comparison?

 

[Mr. Inspector]

A lease line can be between two condos or two stores in the same building and not require any space between them. You could also lease a space in part of a building with a line but no walls between.

 

[Jon Victor]

IBC section 412.3.1 says that Exterior walls located less than 30 feet from lot lines or a public way shall have a fire-resistance rating of not less than 2 hours. Our jurisdiction has decided that a lease line and a lot line are the same and we will require all hangars to be 30' from the lease/lot line or build a 2 hr. exterior wall. The heartburn that I have is the definition is for a "lot line" and not a lease line. I have searched through several airports, SLC being one of them, and they only require 10' from the assumed property line between the two buildings as per IBC table 602.
Has any of your jurisdictions created a policy for hangars and if so, would you please share that for comparison?

What is more restrictive is NFPA 409. Section 10.2 specifies a "clear space" between hangars over a certain size and type of construction... So which one do we enforce, the IBC that references NFPA 409 or the full NFPA code?

 

[e hilton]

Enforce the more restrictive, unless you can find an exception.

 

[Yikes]

A lot line and its location are defined by the subdivision plat that created it. The property line is the same as the lot line at the instant of its platting.
Over time, it can be adjusted from its original location on the plat, at which point the boundary becomes a "property" line.

In any case, lease lines do not necessarily equate to lot lines. I can lease a freestanding apartment buildings in a multifamily apartment development, and the whole property may still have only one lot, as in this example below:






Unless the counrty recorder or title reports or ALTA surveys indicate that a lot line has been recorded that matches the lease lines, then the lease line not a lot line.

 

[Mr. Inspector]

To me the 2018 IBC only requires you to go by NFPA 409 for the fire suppression design..

 

[Jon Victor]

To me the 2018 IBC only requires you to go by NFPA 409 for the fire suppression design..

Why do you think this Rick? Can you explain your reasoning here?

 

[Jon Victor]

Yikes,

I do agree with you about lease lines, but how do we get past NFPA 409 section 10.2.1 that talks about "clear space"? Seems to me like this is the most restrictive requirement. Is there any reason why I shouldn't be enforcing this NFPA requirement?

 

[Mr. Inspector]

[F] 412.3.6 Fire suppression. Aircraft hangars shall be
provided with a fire suppression system designed in accordance
with NFPA 409, based on the classification for the
hangar given in Table 412.3.6.
Exception: Where a fixed base operator has separate
repair facilities on site, Group II hangars operated by a
fixed base operator used for storage of transient air-
[F] 412.3.6.1 Hazardous operations. Any Group III
aircraft hangar according to Table 412.3.6 that contains
hazardous operations including, but not limited to, the
following shall be provided with a Group I or II fire
suppression system in accordance with NFPA 409 as
applicable:
1. Doping.
2. Hot work including, but not limited to, welding,
torch cutting and torch soldering.
3. Fuel transfer.
4. Fuel tank repair or maintenance not including
defueled tanks in accordance with NFPA 409,
inerted tanks or tanks that have never been
fueled.
5. Spray finishing operations.
6. Total fuel capacity of all aircraft within the
unsprinklered single fire area in excess of 1,600
gallons (6057 L).
7. Total fuel capacity of all aircraft within the maximum
single fire area in excess of 7,500 gallons
(28 390 L) for a hangar with an automatic sprinkler
system in accordance with Section 903.3.1.1.

 

[Yikes]

Jon, does The NFPA have a provision similar to IBC 705.3 exc. #1, and would if so, could it apply to your situation, so that several smaller hangers get treated in the NFPA as a single large hanger?

1. Two or more buildings on the same lot shall be either regulated as separate buildings or shall be considered as portions of one building if the aggregate area of such buildings is within the limits specified in Chapter 5 for a single building. Where the buildings contain different occupancy groups or are of different types of construction, the area shall be that allowed for the most restrictive occupancy or construction.

FWIW, I’ve heard the designers of many larger commercial airports (as well as aircraft carriers) will have a Fire Protection Engineer do a performance based code equivalency, so they have other options for life safety besides prescriptive compliance with the IBC and NFPA. They‘ll have specialized suppression systems, an onsite fire station, etc.

 

[Yikes]

You mentioned SLC. Did you see this from nearby Heber City?
In this instance they changed the occupancy from aircraft storage “S” to aircraft museum “A”.
https://heber-ut.granicus.com/MetaViewer.php?view_id=1&clip_id=613&meta_id=54990

Here’s an older thread:
https://www.thebuildingcodeforum.com/forum/threads/s-1-aircraft-hangar-fire-barrier.7628/

 

[Jon Victor]

Yikes, yes the hangar code does have a provision to "cluster" the buildings. We have used that provision in our jurisdiction to group small hangars together, but it doesn't work so well on larger hangers over the 10,000 sq. ft. threshold because the larger ones have already used up all of the allowable area.

 

[Jon Victor]

Rick,

Yes I see what you say about the fire suppression systems. We'd love to see these bigger hangars sprinkler the building because it opens up so many more options when they do that, but our dilemma right now is what do we do with the 30' "lot line" separation from IBC section 412.3.1, or if we don't enforce that rule because there aren't true lot lines, only "lease lines" and just use IBC table 602 and assume an imaginary line between the building which would only require 10' without the sprinkler.
If we use the most restrictive provision like was mentioned above, NFPA 409 would apply and there would need to be 50' of "open space" between buildings.

 

[MtnArch]

Lease lines can be modified easily by the lessee and the lessor at any time. If the jurisdiction is mandating that the lease line act as the property line they may have a much larger issue if the airport manager changes the lease in the future that either adds more lease lines or moves the lease line. We have a hangar project right now that the lessee needs to expand and the airport is modifying the lease to move the lease line to accommodate that expansion.

 

[Mr. Inspector]

Rick,

Yes I see what you say about the fire suppression systems. We'd love to see these bigger hangars sprinkler the building because it opens up so many more options when they do that, but our dilemma right now is what do we do with the 30' "lot line" separation from IBC section 412.3.1, or if we don't enforce that rule because there aren't true lot lines, only "lease lines" and just use IBC table 602 and assume an imaginary line between the building which would only require 10' without the sprinkler.
If we use the most restrictive provision like was mentioned above, NFPA 409 would apply and there would need to be 50' of "open space" between buildings.

I don't know, I don't have NFPA 409. I don't know if the if the separation requirement is in the fire suppression system sections of NFPA 409.

 

[steveray]

I don't know, I don't have NFPA 409. I don't know if the if the separation requirement is in the fire suppression system sections of NFPA 409.

I think it is one of the things that gives a pass....Just dealing with something similar now and seems to a bit of a circular reference....

 

[Builder Bob]

You must look at the referenced code in chapter 45 ??? (so many code cycles that I have lost count) This will directly refernce the extent of a refernce stadard that can be enforced -

 

[Builder Bob]

Correction Chapter 35 - of the building code