New Cal Fire setback requirement for roof mounted solar?

[J.P.M.]

I think even 16% is pretty substantial especially here in northern california. many houses are two story homes, and the second floor is usually much smaller than the first floor, and the usable roof over the first floor is pretty limited. additionally, the second floor roof is usually pretty cut up. My house is a maximum lot coverage single story house, and it was difficult to use a panel other than sunpower to get the capacity i wanted. my builder had to use 3 or more roof surfaces and therefore less efficient directions. basically, my builder who isn't a sunpower dealer couldn't match my sunpower quote for 21 x-21 345 panels with his panels. My roof is very cut-up except for one roof, and it can hold 21 panels assuming no 36" boundary. So, even without the 36" boundary, my builder couldn't compete. What will happen now with the 36" boundary restriction? Much of my roof isn't 114" of clear space, i.e. 72" + 42", so much of my roof can't even get one panel on it. I really think the area advantage will become bigger and bigger. I guess time will tell.

I see other people quoting 250W, 280W, etc, so at 250W, that is 95/250 == 38%, 65/280 == 23.2%. Those are some big area increases if you don't have the space. Also, it will most likely be even higher, because you will need to put panels on less optimal roofs, therefore requiring even more panels, and the equation becomes even worse.

Sunpower is great stuff and it's a free country. IF you are space limited it may be worth the 20 - 30% price premium for the Sunpower.

[russ]

LG 300's will yield ~182 W/m^2 -->> ~16% advantage which is the lower end of my estimate.

(

Right - it is 16% for the LG compared to Sun Power

[eugenep]

No. Just running somw #'s. Read my post. I wrote AREA efficiency advantage. Not conversion efficiency.

Sunpower 345 area ~= 1.63 m^2.

Old LG 250 area ~= 1.61m^2

-->> (345/1.63)_= 212 W/m^2 @S.T.C. as published.

(250/1.61) = 155 W/m^2 @ S.T.C. as published.

LG 300's will yield ~182 W/m^2 -->> ~16% advantage which is the lower end of my estimate.

(212-155)/155 ~= 37% increase in area efficiency.

I think even 16% is pretty substantial especially here in northern california. many houses are two story homes, and the second floor is usually much smaller than the first floor, and the usable roof over the first floor is pretty limited. additionally, the second floor roof is usually pretty cut up. My house is a maximum lot coverage single story house, and it was difficult to use a panel other than sunpower to get the capacity i wanted. my builder had to use 3 or more roof surfaces and therefore less efficient directions. basically, my builder who isn't a sunpower dealer couldn't match my sunpower quote for 21 x-21 345 panels with his panels. My roof is very cut-up except for one roof, and it can hold 21 panels assuming no 36" boundary. So, even without the 36" boundary, my builder couldn't compete. What will happen now with the 36" boundary restriction? Much of my roof isn't 114" of clear space, i.e. 72" + 42", so much of my roof can't even get one panel on it. I really think the area advantage will become bigger and bigger. I guess time will tell.

I see other people quoting 250W, 280W, etc, so at 250W, that is 95/250 == 38%, 65/280 == 23.2%. Those are some big area increases if you don't have the space. Also, it will most likely be even higher, because you will need to put panels on less optimal roofs, therefore requiring even more panels, and the equation becomes even worse.

[J.P.M.]

Playing with words again?

SunPower = 21.5% efficient
Canadian Solar = 15.9%
LG = 18.3%

Now where do we come up with 38 to 40%?

No. Just running some #'s. Read my post. I wrote AREA efficiency advantage. Not conversion efficiency.

Sunpower 345 area ~= 1.63 m^2.

Old LG 250 area ~= 1.61m^2

-->> (345/1.63)_= 212 W/m^2 @S.T.C. as published.

(250/1.61) = 155 W/m^2 @ S.T.C. as published.

LG 300's will yield ~182 W/m^2 -->> ~16% advantage which is the lower end of my estimate.

(212-155)/155 ~= 37% increase in area efficiency.

[Naptown]

Playing with words again?

SunPower = 21.5% efficient
Canadian Solar = 15.9%
LG = 18.3%

Now where do we come up with 38 to 40%?

21.5 - 15.9 = 5.6
5.6/15.9= 35.2

[russ]

The 240's were physically smaller. The Sunpower AREA efficiency advantage tends to run about 25-30% max. comparing other manufacturers' current panels, down to about 15 % advantage or so for some comparisons. Might be ~38-40% if you compare older panels to a Sunpower 345, but I don't know if that's a fair comparison.

I suggested in a previous post that this setback business might be a gifted marketing advantage for Sunpower, making me wonder if they would become cheerleaders for fire safety.

Playing with words again?

SunPower = 21.5% efficient
Canadian Solar = 15.9%
LG = 18.3%

Now where do we come up with 38 to 40%?

[J.P.M.]

No, that was my quick calculation in my head. I thought that many company's solar panel are rated for around 240 watts and the sunpower x21 which I am geting is 345 watts for the same size. 105/240 is 43.75%. The 43.75% is my calculated number. Is that not correct?

My salesman told me the 36" rule was going to be enforced in my town on Jan 1, 2014, so get my permits approved before then. I am closer than the 36" to both ridge and edge. He made no reference to the performance advantages of their panels.

The 240's were physically smaller. The Sunpower AREA efficiency advantage tends to run about 25-30% max. comparing other manufacturers' current panels, down to about 15 % advantage or so for some comparisons. Might be ~38-40% if you compare older panels to a Sunpower 345, but I don't know if that's a fair comparison.

I suggested in a previous post that this setback business might be a gifted marketing advantage for Sunpower, making me wonder if they would become cheerleaders for fire safety.

[russ]

No, that was my quick calculation in my head. I thought that many company's solar panel are rated for around 240 watts and the sunpower x21 which I am geting is 345 watts for the same size. 105/240 is 43.75%. The 43.75% is my calculated number. Is that not correct?

You are talking about physical size - not efficiency - Sun Power does have a bit higher efficiency but not 44%

[eugenep]

Wow! That is what the salesman told you? Without any reference I guess it could be true but in the real world it ain't so.

No, that was my quick calculation in my head. I thought that many company's solar panel are rated for around 240 watts and the sunpower x21 which I am geting is 345 watts for the same size. 105/240 is 43.75%. The 43.75% is my calculated number. Is that not correct?

My salesman told me the 36" rule was going to be enforced in my town on Jan 1, 2014, so get my permits approved before then. I am closer than the 36" to both ridge and edge. He made no reference to the performance advantages of their panels.

[russ]

That's why I think that Sunpower will become an even bigger player, because it gets you 30-40% more per sq ft.

Wow! That is what the salesman told you? Without any reference I guess it could be true but in the real world it ain't so.

[eugenep]

sunpower increases their advantage

OverTheSun,
Thanks for the advice. I will circle back with my contractor and try to pursue #1 and #2. My contractor says that they have had success getting exceptions in SD county. Hoping for the same in my case. I will post an update when I get any new information.

My installer told me about the code change, so I rushed to get my permit before the deadline. It was just luck on my part that I talked with an installer before the deadline. My house won't be completed until summer. That's why I think that Sunpower will become an even bigger player, because it gets you 30-40% more per sq ft.

[ocdave]

I think we kind of touched on this before. The CA code section that deals with this is
Title 24, Part 9, Chapter 6, Sec. 605.11. The setbacks specifically start at Sec. 605.11.3. This section provides and exception that states:

2. Panels/modules shall be permitted to he located up to the roof ridge where an alternative ventilation method approved by the fire chief has been provided or where the fire chief has determined vertical ventilation techniques will not be employed.

Your local building department probably can't help you - they are just implementing the code and may not have the authority to grant an exception, but there might be someone higher up than a clerk who could grant an exception. I think you have three (at least) options that are not mutually exclusive.

1. Contact the building permit dept. and find out what the appeal process is for a denied permit application.

2. Contact the local fire chief and ask for an evaluation of your proposed PV system, explaining your situation and the fact that only 30% of your roof would be covered by the PV system and there would be alternative access routes and ventillation areas and ask for a letter stating that s/he approves an alternative ventilation method (i.e., access from route on a roof slope other than the one you intend to put panes on). If s/he agrees, then you should be able to point to the above provision of CA code to get your permit.

3. Contact the State Fire Marshall and ask for a code interpretation. http://osfm.fire.ca.gov/codeinterpre...rpretation.php
This option carries the risk that State Fire Marshal does not give a favorable interpretation, then 1 and 2 would not be able to overcome her decision. Then the only recourse would be to have the code changed, which is possible, but longer term and more political.

I would check out #1 first and then #2, saving #3 for the last resort.

# 3 is something I've been considering doing myself, but I have been massively busy at work. I'm going to PM you. Maybe we could work together on this.

OverTheSun,
Thanks for the advice. I will circle back with my contractor and try to pursue #1 and #2. My contractor says that they have had success getting exceptions in SD county. Hoping for the same in my case. I will post an update when I get any new information.

[Naptown]

Good Luck my friend.

Which is less expensive?

1. Fight and win, which is a gamble?
2. Comply and take your loss?

Pointing out their enforcement error costs nothing and everything to gain.
complacency cost hundreds of thousands on these projects and future ones.

[Naptown]

Where's SEIA through all this ? Seems like they'd have a stake in this - perhaps nationwide it would seem. Are they even around anymore ?

Screwed up big time but a bit late now

[J.P.M.]

About to enter into a P***ing match with the local city next week. They have been enforcing the NFPA1-2012 which this all stems from.
They have adopted this code and reference it but in the city code they adopted and promulgate the code as adopted by the state of Maryland.
The state specifically excludes one and two family dwellings.

Where's SEIA through all this ? Seems like they'd have a stake in this - perhaps nationwide it would seem. Are they even around anymore ?