What is considered a roof obstruction when mapping out fire pathways?

[K1NGWALNUT]

Hello,

Is there a minimum height that a pipe, vent, skylight, etc needs to be before it is considered an obstruction to the fire walkway?
For example, I need a 3ft setback from the ridge, but within that 3ft there is a skylight protruding 3" off the roof surface. Will my setback need to go around that skylight? Not sure if there is a general rule from the NEC/IFC or if this is something more municipal, but I am not finding anything on this. I am in California.

 

[don_resqcapt19]

The intent is to provide a walkway for fire fighters. They can't walk on the skylight, so it is my opinion you must provide a 3' setback around the skylight. This is not a rule in the NEC. It is found in the national and local building codes.

 

[Hv&Lv]

See if this helps

Roof Fire Setbacks and pathways for Residential Solar PV Systems | San Diego Solar Permits

According to Cal Fire’s Solar Photovoltaic Installation Guidelines below are illustrations of currently enforced fire setbacks/pathways for residential solar system installations. Any roof with pitch equal or less than 2 in 12 (9.46 degrees) doesn’t require any setbacks/pathways. Full text of...

www.sandiegosolarpermits.com

 

[jaggedben]

I've never seen any code that directly addressed this question with specifics. I always used my judgement. I often ignored small plumbing vents in pathways. But I agree that a skylight obstructs the pathway. So would a chimney or anything else too large to step around or over without leaving the pathway. Occasionally it's not your fault that pathways are obstructed by other objects. (We might ask why these pathways are only required around solar panels and not generally for all buildings and obstructions.) But you need to make a good faith effort to keep the required pathways open.

 

[don_resqcapt19]

I've never seen any code that directly addressed this question with specifics. I always used my judgement. I often ignored small plumbing vents in pathways. But I agree that a skylight obstructs the pathway. So would a chimney or anything else too large to step around or over without leaving the pathway. Occasionally it's not your fault that pathways are obstructed by other objects. (We might ask why these pathways are only required around solar panels and not generally for all buildings and obstructions.) But you need to make a good faith effort to keep the required pathways open.

Because solar panels are the only things that cover such a large part of the roof...without the fire walkways, they would cover 100% of the roof and impede firefighting activities such as roof venting.

 

[jaggedben]

Because solar panels are the only things that cover such a large part of the roof...without the fire walkways, they would cover 100% of the roof and impede firefighting activities such as roof venting.

Yeah, I get that, mostly. But it has felt unfair when I go up to measure a residential roof and have to lose some solar panels because other obstructions are already placed in the natural pathway locations. Also the OP mentioning a skylight is apt ; sometimes large/multiple skylight assemblies or atrium cutouts cover almost as large a part of a roof plane as solar panels would.

The following is a kind of a minor side case, but still a case in point. San Francisco has its own fire pathway rules because the houses are all built right against each other: they require the first 3ft streetside to be clear, and a 3ft path from the front to the rear. Well, a couple times I get on the roof pre-installation and there is no existing 3ft path to the rear. The widest path is only 2ft or 18" wide, hemmed in by skylights and light wells and such. (These are flat roofs.) So it's kind of BS that they never enforced the 3ft path from front to rear until solar panels came along. It was rare but it happened.

 

[jaggedben]

Also we have to keep the ridge clear for venting but other trades can load up dozens of obstructions in the same area if they want. I mean, I kinda don't mind, on new construction and remodels we just tell the GC to have other trades put all their vents in the ridge setback. So then much of the ridge setback is (I presume) too cluttered for venting operations. Does this actually make sense?

 

[Hv&Lv]

I've never seen any code that directly addressed this question with specifics. I always used my judgement. I often ignored small plumbing vents in pathways. But I agree that a skylight obstructs the pathway. So would a chimney or anything else too large to step around or over without leaving the pathway. Occasionally it's not your fault that pathways are obstructed by other objects. (We might ask why these pathways are only required around solar panels and not generally for all buildings and obstructions.) But you need to make a good faith effort to keep the required pathways open.

This isn’t required or adopted by all locals?
I see it on some permit applications.

https://www.calbo.org/sites/main/files/file-attachments/brooks-fire-guidelines-webinar-nov2010.pdf

 

[jaggedben]

This isn’t required or adopted by all locals?
I see it on some permit applications.

https://www.calbo.org/sites/main/files/file-attachments/brooks-fire-guidelines-webinar-nov2010.pdf

Sorry if I wasn't clear. Fire pathways are definitely required everywhere. What's not specified is how big or numerous obstructions have to be to 'disqualify' a pathway. To quote from you link above, "Pathways shall be located in areas with minimal obstructions such as vent pipes, conduit, or mechanical equipment." What is 'minimal'? It's up to you to work that out with the AHJ.

 

[jaggedben]

In my judgment and experience, a couple 2" plumbing vents in a pathway is minimal. One conduit crossing over to the gable is minimal. A 14" wide by 16" tall roof or heating vent? Probably not. A skylight that protrudes 3" into one side of the pathway? I hope maybe that's 'minimal'. A skylight protruding 11" into the pathway? I'll put my pathway somewhere else. Just my 2 cents.