Ventilation/Air-conditioning system for battery room 1

• Aug 25, 2006

• #2

walkes

Mechanical

Mar 28, 2002

362

CA

Put Hydrogen gas sensors in the space, if the concentration hits 2% by volume eliminate the recirculation. Shut down A/C units and exhaust the space entirely. You may want to review the appropriate NFPA documents for your situation. The battery room sounds similar to a telecommunications facility (see NFPA 76).

 

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• Aug 25, 2006

• #3

hagl0048

Mechanical

Aug 25, 2006

1

US

What you need to do is figure out what the CFM (cubic feet per minute) requirements of exhausting for this type of room is. Then be constantly exhausting that amount, and replacing the exhausted amount with outdoor air. Also, have an H2 sensor connected to a make-up air unit and a second exhaust fan. So, when the H2 sensor is triggered, the second exhaust fan will turn on with the make-up air unit, to bring the H2 levels down.

 

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• Aug 25, 2006

• #4

AbbyNormal

Mechanical

Nov 17, 2003

780

KY

this like a rectifier room in a telco?

 

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• Aug 25, 2006

1
• #5

M

MintJulep

Mechanical

Jun 12, 2003

10,244

JP

Google is an amazing thing.

http://www.cholarisk.com/Files/Risk...y Rooms.pdf#search="battery room ventilation"

http://www.cdtechno.com/cd/library/papers/9904pdf.htm

http://www.battcon.com/PapersFinal2002/VaccaroPaper2002.pdf#search="battery room ventilation"

and many more.

 

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• Aug 28, 2006

• #6

LSA

Mechanical

Mar 30, 2005

36

US

I agree with Walkes...

Design a passive exhaust system to be activated when the H2 sensors alarms at 1% or 2% H2 concentration by volume and also shut down the AC system.

During normal operation the room can be 100% recirculated.

A simple formula we use to calculate the minimum required exhaust CFM is:

CFM = G / P / 60
where:
G = Gassing rate of batteries at worst case condition [ft^3/hr](gassing rate provided by battery MFR)
P = Maximum percentage of H2 concentration allowed. (Our local codes mandates a 1% or P = 0.01)

 

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• Aug 28, 2006

• #7

LSA

Mechanical

Mar 30, 2005

36

US

Also, make sure the exhaust fan is of spark/explosion construction and the powered by emergency power (if available).

 

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• Aug 28, 2006

• #8

berkshire

New member

Jun 8, 2005

4,429

US

Whilst AGM batteries tend not to do this, Flooded batteries, when over charged will sometimes emit an aerosol spray of sulphuric acid.
Can the materials around the area handle this?
B.E.

 

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• Aug 29, 2006

• Thread starter
• #9

wendee

Electrical

Aug 25, 2006

4

JP

Thank you guys for your replies. Those are very informative.

Though A/C unit cannot be shutdown as it is required to maintain the room temperature for the battery.

Usually, one air flow is used for battery rooms and discharged all air outside. But in this case, large capacity of A/C unit is needed. So to save energy and to reduce the capacity, air is recirculated. Unfortunately, H2 is mixed with air.

Is it possible to have a valve in the duct to close if set percentage of hydrogen is reached then discharge it into the air? And open it once H2 level goes down?

Is it allowed and safe for operation?

Thank you for your time.

 

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• Aug 29, 2006

• #10

LSA

Mechanical

Mar 30, 2005

36

US

It is possible to have the H2 sensor activate a damper actuator but the important question is whether your local jurisdiction will allow it. Check with your building dept & fire dept.

 

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• Sep 12, 2006

• #11

kbragan

Industrial

Sep 12, 2006

1

US

i was browsing the site and thought you might find this link helpful in regards to H2 detection in batttery rooms

http://www.rkiinstruments.com/pdf/hydrogenbatteries.pdf

 

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• Sep 12, 2006

• Thread starter
• #12

wendee

Electrical

Aug 25, 2006

4

JP

Wow! Thank you so much for your replies. I told my boss about putting a hydrogen gas detector. And they are considering and proposing it to the plan. Though I haven't found in NFPA standards that allow for recirculation, but they stated proper ventilation. So I believe, we could work it out.

Thank you guys for your help and God bless!!

 

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