Firefighter's fears

[s-park-er]

I was greeted with this news story on my feeds this morning and thought I would stir up some comments from the group. What say you to this article?

http://www.foxnews.com/us/2013/10/02/firefighters-alarmed-by-dangers-posed-by-rooftop-solar-panels/

Just because I like to stir things up...:angel:

 

[iwire]

Well, if the FFs determine someone's panels make it to dangerous to go on the roof they should stay off the roof.

Seems pretty simple to me.

 

[petersonra]

let it burn if it is too dangerous to fight the fire.

 

[K8MHZ]

let it burn if it is too dangerous to fight the fire.

Micro-cosmically, that is a good solution. But, not being able to put out the fire drastically increases the risk of the fire spreading to other structures and nasty chemicals catching fire, possibly exploding and contaminating the air.

This subject was brought up in a solar installation class I took a couple years ago. I knew the local fire chief at the time and his stance was 'just let it burn', also. Along with, 'what else are we supposed to do?'.

Having friends that are firefighters, I am against any unnecessary encumbrances on their performance. I don't have an answer, but I am against the present status quo.

 

[petersonra]

perhaps a requirement that any structure with a PV system on the roof must have a sprinkler system.

 

[iwire]

Having friends that are firefighters, I am against any unnecessary encumbrances on their performance. I don't have an answer, but I am against the present status quo.

As much as I respect FFs and what they do I also find they think the world has to revolve around their jobs.

How is a solar panel installation any different than a commercial or industrial building loaded with roof top equipment?

 

[BillK-AZ]

The foxnews.com article is simply one-sided. Too bad they could not be bothered to illustrate the article with a photo of PV on roofs and not an array field. Last I heard was that the NJ fire did not start with the PV, and was basically a cooking oil fire that even with roof access most likely could not be extinguished. The NJ roof array was not installed according to the fire access code shown below (one can measure the array on the Google Earth image before the fire).

These issues have been addressed for years and various 'hazards' are now addressed by the NEC (Art 690.4(F), for instance), International Fire
Code (2012 edition, Section 605.11), etc.

The International Fire Code is copyrighted, a direct link is not known, but many cities have adopted section 605.11 dealing with fire personnel access on roofs, maximum areas, etc. The City of Phoenix has most of this posted at:

http://phoenix.gov/webcms/groups/internet/@inter/@dept/@fire/@prev/documents/web_content/092509.pdf

The Solar America Board for Codes and Standards (Solar ABCs)(http://solarabcs.org/index.html) has major efforts in these areas and followers of this forum should keep an eye on these.

There is much work underway to define these hazards and determine the best solutions. One interesting major report is:

http://www.ul.com/global/eng/pages/...buildingmaterials/fire/fireservice/pvsystems/

 

[ggunn]

As much as I respect FFs and what they do I also find they think the world has to revolve around their jobs.

How is a solar panel installation any different than a commercial or industrial building loaded with roof top equipment?

The difference is that the solar modules on the roof are a source of electricity while the rest of the rooftop equipment consumes electricity. Killing power to the building shuts down the power lines to rooftop HVAC, etc. while the DC conductors from the PV modules are still live.

 

[iwire]

The difference is that the solar modules on the roof are a source of electricity while the rest of the rooftop equipment consumes electricity. Killing power to the building shuts down the power lines to rooftop HVAC, etc. while the DC conductors from the PV modules are still live.

If I recall the primary beefs presented where access and the added weight of the installation.

 

[ron]

This is a pretty long UL report, but interesting

http://www.ul.com/global/documents/...rials/fireservice/PV-FF_SafetyFinalReport.pdf

The panels need to be covered, but what if you can't get up there to cover them?

 

[don_resqcapt19]

As much as I respect FFs and what they do I also find they think the world has to revolve around their jobs.

How is a solar panel installation any different than a commercial or industrial building loaded with roof top equipment?

While the added weight and the DC power from the panels is an issue, to me the bigger issue is the loss of the ability to vent the fire. In many cases there is not enough space to cut a big enough vent hole or holes.

 

[iwire]

While the added weight and the DC power from the panels is an issue, to me the bigger issue is the loss of the ability to vent the fire. In many cases there is not enough space to cut a big enough vent hole or holes.

I understand but it just becomes a question of where to draw the line on what an owner is required to do in order to make firefighting easier. There are no end to things that could be done to make firefighting easier.

From my limited time doing solar I learned it is surprisingly difficult to fit all the panels needed on a roof to reach the output you desire. Shadows are killers so you already limited by RTUs, chimneys, plumbing vents, setback from the roof edge etc.

 

[ggunn]

If I recall the primary beefs presented where access and the added weight of the installation.

Access is indeed an issue; PV systems in some locations are restricted in how much of the roof they can cover and where walkways have to be left open. The most commonly raised issue I have heard, however, is that of energized conductors on the roofs that are still live when building power is cut off.

 

[jaggedben]

A couple points...

1) The 2014 code will contain a requirement that a 'rapid shutdown system' denenergize all photovoltaic conductors more than 10ft from an array. That I think will address one of the biggest concerns about energized conductors that the firefighters can't turn off, which in my opinion is the only real firefighter concern that stands far out in front of others. Note that systems with microinverters or some DC optimizers already have this feature.

2) In most residential cases the risk of panels causing a roof to collapse is pretty negligible, as usually the roofing materials themselves weigh quite a bit more than the panels. If the roof supports burn then there's a risk of collapse regardless. Some buildings need to be structurally improved when arrays are installed, but if that's done right then I don't really buy this as a severe additional concern.

3) In California the state fire marshall first issued guidelines several years ago to ensure that firefighters have both pathways and places to vent the roof. So at least in Cali, I take issue with the "codes need to catch up" statement in the article. Enforcement may need to catch up and be consistent. The code is already there.

 

[petersonra]

Perhaps a partial solution is some kind of melting alloy type disconnect built into the PV itself. sort of like how fire sprinklers work.

 

[jaggedben]

perhaps a requirement that any structure with a PV system on the roof must have a sprinkler system.

For commercial and new residential construction, ok. For residential retrofits, please, please, no. A rule that basically amounts to prohibiting residential solar goes too far. Just let the fire insurance companies increase premiums, and leave it at that.

(Also, if the solar is what increases the fire risk, and it's all on top of the roof, what good is a sprinkler system going to do?)

 

[GoldDigger]

(Also, if the solar is what increases the fire risk, and it's all on top of the roof, what good is a sprinkler system going to do?)

It reduces the need for the fire fighters to cut holes in the roof to pour in water. If you can keep the fire from spreading to involve the attic space, your need to ventilate and water the attic is reduced.

If the fire starts in the attic, you are just screwed unless you put sprinklers there too.

In the case of a flat roof (mostly commercial), the same principle still applies of limiting the spread of the fire to the roof supports, etc.

Note: In residential buildings the sprinklers are by design there just to slow the fire down enough for the occupants to escape.
In commercial buildings the sprinklers are (usually) designed to limit the spread of the fire and the fire damage to the building contents.

 

[ggunn]

In commercial buildings the sprinklers are (usually) designed to limit ... the fire damage to the building contents.

And replace it with water damage.

 

[GoldDigger]

And replace it with water damage.

Absolutely!

 

[K8MHZ]

It reduces the need for the fire fighters to cut holes in the roof to pour in water. If you can keep the fire from spreading to involve the attic space, your need to ventilate and water the attic is reduced.

If the fire starts in the attic, you are just screwed unless you put sprinklers there too.

In the case of a flat roof (mostly commercial), the same principle still applies of limiting the spread of the fire to the roof supports, etc.

Note: In residential buildings the sprinklers are by design there just to slow the fire down enough for the occupants to escape.
In commercial buildings the sprinklers are (usually) designed to limit the spread of the fire and the fire damage to the building contents.

The main reason firefighters cut holes in the roof is for venting. Explosive gasses can build up in a fire and case a flashover. Venting lets those gasses out, along with smoke, the removal of smoke making it easier for the firefighters in the building to be able to see.