Also look to see if the fire code in your state has additional
restrictions.
In New York Stat, the 2010 Fire Code contains a section (608) with
more regulations to be heeded when installing 'stationary storage
batteries'.
-Glenn
*From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org]
*On Behalf Of *Drake
*Sent:* Tuesday, July 29, 2014 12:01 PM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Batteries in a dwelling - Venting
Concorde AGMs
This is a reply to a post by Alan from June 21st. I'm replying because
I've had to deal with this issue also. It seems to me that the 2014
NEC Handbook is _fairly_ clear that we are not required to vent any
batteries to the outside.
*"480.9 Battery Locations
*Battery locations shall conform to 480.9(A), (B), and (C).
*(A) Ventilation. *Provisions appropriate to the battery technology
shall be made for sufficient diffusion and ventilation of gases
from the battery, if present, to prevent the accumulation of an
explosive mixture.
Ventilation is necessary to prevent classification of a battery location
as a hazardous (classified) location, in accordance with
Article 500.
Mechanical ventilation is not mandated. Hydrogen disperses
rapidly and requires little air movement to prevent accumulation.
Unrestricted natural air movement in the vicinity of the battery,
together with normal air changes for occupied spaces or heat
removal, normally is sufficient. If the space is confined, mechanical
ventilation may be required in the vicinity of the battery.
Hydrogen is lighter than air and tends to concentrate at ceiling
level, so some form of ventilation should be provided at the
upper portion of the structure. Ventilation can be a fan, roof ridge
vent, or louvered area.
Although valve-regulated batteries are often referred to as
"sealed," they actually emit very small quantities of hydrogen gas
under normal operation and are capable of liberating large quantities
of explosive gases if overcharged. These batteries therefore
require the same amount of ventilation as their vented
counterparts."
I think that the confusion come is with the statement "These batteries
therefore
require the same amount of ventilation as their vented
counterparts."
As we see from the statement "Unrestricted natural air movement in the
vicinity of the battery,
together with normal air changes for occupied spaces or heat
removal, normally is sufficient," the concern is with explosive gasses
being restricted to a small area, where explosive concentrations of
hydrogen can build up.
The article also has the statement "Provisions appropriate to the
_battery technology_" which should be taken into account. In practice,
liquid electrolyte batteries stink and emit toxic fumes, so we do vent
these outside.
It does sound like different voices have worked their way into this
code section, which can open the way to various interpretations. But,
if you look at the photos in the NEC Handbook of batteries, they are
on unenclosed racks inside of a building.
Drake
At 12:06 AM 6/22/2014, you wrote:
Bob,
We had a case in February in which an AHJ insisted that we vent a
Midnite cabinet with a dozen 2V 9150T batteries. We fought it all the
way to the state Technical Advisory Committee, the top arbiter of Code
issues. We fought to a draw: we finally agreed to put in the vent to
get our final passed, and the committee permanently tabled the issue
so there is no precedent set. To continue to fight this would have
required bringing in professional engineers, as some of the committee
members were reluctant to make their own decisions about the issue and
wanted to pass the buck. As I recall, the Zephyr Power Vent was
ultimately never hooked up to the Classic controller's auxiliary, as
the necessary work was handled by the GC (rather than by us) at a
quite remote location. The challenge to the AHJ was a pain in the
butt, although we were paid by the clients for the effort, as they
agreed with the absurdity of the inspector's demand.
I have attached a few documents I gathered and prepared in this case.
You do not need to vent AGMs if the larger space in which the battery
enclosure is located has a typical and normal amount of natural air
circulation and convective air exchange. Also, you can't duplicate
what Kevin describes below with a vented enclosure - Kevin's approach
requires a "sealed and vented battery enclosure". By design, your
enclosure is unsealed.
Putting in vents "for the next guy" also makes no sense. If you
install 8 flooded L16s on two shelves in a Midnite MNBE-Cl16
enclosure, you won't be able to routinely add water to the cells. The
cabinet was designed and built for VRLA batteries. So any venting you
install now would have to be redone to fit a cabinet built for flooded
batteries with top access.
Allan
*Allan Sindelar*
al...@sindelarsolar.com <mailto:al...@sindelarsolar.com>
NABCEP Certified PV Installation Professional
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder (Retired), Positive Energy, Inc.
*505 780-2738 cell*
On 6/21/2014 1:30 PM, Bob Clark wrote:
RE-Wrenches:
2014 NEC 480.9 (A) has two informational notes that seem to point to
the possibility of not having to vent AGMs.
Here is what I was going to do with 8 Concorde SunXtender Batteries,
6V, 405Ah, L16, PVX-4050HT:
1. Put them in a Midnite Solar, MNBE-CL16 Battery Enclosure (which is
not a sealed box) in a "battery closet."
2. Vent the box out of the top of the box and through the wall of the
house with pipes like Kevin Pegg suggests.
Do any of you see any problems with this? Venting unnecessary?
One consideration is the "next guy" who occupies this house may want
flooded batteries, in which case, the vent system would definitely be
necessary.
Bob Clark
bcl...@solar-wind.us <mailto:bcl...@solar-wind.us>
On Apr 4, 2014, at 2:49 PM, Kevin Pegg <kp...@energyalternatives.ca
<mailto:kp...@energyalternatives.ca>> wrote:
Hi William,
In the cold north here in Canada, this is the most common way we
install batteries - within the heated envelope of a home or shop,
installed in a sealed & vented battery enclosure.
Hydrogen is easy to vent as it is lighter than air. We use a process
similar to below. I see a lot of installations with power vents that
are not done properly - exhaust only but no intake as example. They
can also fail. Or installed in such a way that outside wind influences
could actually reverse the flow and pressurize the battery box! Air
flow needs to be balanced.
http://www.bdbatteries.com/hydrogenventing.php
To remove the thermal air currents present in a battery box venting
system, you must create a natural heat sink between the vent tubes to
neutralize the difference in temperature. This in turn will stagnate
the air, allowing the hydrogen which is lighter than air, to rise and
escape the battery box. Make sure the smaller tube, the one inside,
extends to the bottom of the box. This will allow "heavier" fresh air
to fall to the floor of the box and retard hydrogen entry. The intake
for the hydrogen is at the top of the box, the exterior tube in the
system. Hydrogen will travel in the opposite direction through the
larger outer pipe as it is lighter than the air surrounding it.
Several good methods for constructing this vent system exist, we
particularly like to see 1/2 inch copper pipes inside 1 inch pipe. Any
highly conductive metal pipe will work it will transfer heat quickly.
Galvanized, steel, and other pipes that spark when rubbed aren't as
great. DO NOT USE THESE IN EARTHQUAKE ZONES.
DO NOT USE PVC FOR THIS VENT SYSTEM....PVC DOES NOT CONDUCT HEAT WELL
ENOUGH! Copper, aluminum, and other non sparking conductive metals are
great!
<Outlook.bmp>
<Outlook.bmp>
-----Original Message-----
From: re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>
[mailto:re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>]On Behalf Of
will...@millersolar.com <mailto:will...@millersolar.com>
Sent: April 4, 2014 9:29 AM
To: RE-wrenches
Subject: [RE-wrenches] Batteries in a dwelling
Friends:
I am proposing installation of vented batteries in a first floor
garage of a dwelling. The dwelling areas are on the second floor. I
am nervous about the cohabitation of batteries and humans.
I reviewed the NEC and could not find any prohibition. Do any of you
have any advice on how this is accomplished in the mot safe manor?
I presume good ventilation and an otherwise sealed room are advised.
I will propose additional smoke detectors, locked doors and I will
research hydrogen detectors. A good spill kit and all PPE will be
staged as usual.
Thanks in advance for the forthcoming, always expert advice.
William Miller
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