A FORUM FOR FIRE PROTECTION QUESTIONS & PE EXAM PROBLEMS | SUBSCRIBE NOW
|
First of all I work at a gas company as a Fire Equipment Maintenance Specialist in Libya. My job is to follow up and assess efficiency of fixed firefighting systems and provide plans for preventative/corrective maintenance/testing based on schedules.
One of our firefighting systems has a foam bladder tank which protects an oil tank and plant operations. My problem is when we started this project the bladder tank was built out of global standard. The foam concentrate AFFF is stored between the internal tank wall and membrane. Water gets inside the membrane which forces the foam to get out through the rated membrane. I know it is wrong and does not produce a perfect foam solution within the specification. When I complained about this case, my manager asked me to provide an opinion based on international standards. Is there guidance within NFPA-standards that can help me address this issue? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
5 Comments
MEDJBER AHCENE
12/31/2019 10:35:31 am
It is not a problem of compliance to any regulation. It is a technical matter that should be delt with the manufacturer of the bladder tank. Foam concentrate is a very corrosive product, it should not be in contact with the metal ( the tank surface ) . That 's why it should be contained inside the bladder which is in PVC material.
PETE
12/31/2019 10:46:41 am
The way that most AFFF bladder tanks I've dealt with are designed to operate is the foam concentrate is inside the bladder, and upon system activation water flows betwwen the bladder and tank wall forcing the concentrate out of the top. The concentrate is introduced to the water supply through a proportioner which is a side tap at the throat of a venturi orifice located on the system riser. Concentration is controlled by the diameter of the tap and the siphon force created by the differential pressure across the venturi converging diverging nozzle. Downstream of the proportioner is a test outlet with control valve NC and a bypass control valve NO. The standard is that the concentration is tested at various flow rates at the time of the installation prior to putting the system in service. I would contact ChemGuard or some other internationally recognized vendor that produces NFPA compliant systems.
Mike
12/31/2019 04:51:39 pm
Refer to NFPA 11.
Mike
1/3/2020 12:01:52 am
Can you provide the manufacturer's name and listing information? Leave a Reply. |
Free SignupSubscribe and learn something new each day:
CommunityThank You to Our Top
August 2020 Contributors!
Your PostThe ToolkitSprinkler Designer or Engineer?
Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more: 
Filters
All
Archives
September 2020
Daily
Daily discussions are open-ended fire protection, fire alarm, and life safety questions submitted anonymously for the benefit of sharing expertise and learning from other perspectives. Anyone can submit a question here:
Exam Prep
2020 PE Prep Guide
(Available Now!) 
PE Prep Series
(Available Now!) 2020 PE Prep Series
Current Leaderboard (Click to enlarge) 
PE Problems
Visit July-October for daily Fire Protection PE Exam sample questions.
Solutions are posted the day after posting. Comment with your solutions, questions or clarifications. Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves. |
RSS Feed
