ask for make-up time to refill fire water tanks

[taoxianwen123]

everybody,I want to ask how long it required to refill the fire water tanks after a fire in oil & gas separation plants,and which standard can I find the requirement of make-up time?
In chinese standards, the fire water make-up time is not longer than 96h in oil & gas separation plants, and not longer than 48h in oil refineries,but I can not find the requirements in international standard.can somebody tell me?

[taoxianwen123]

why dose nobody know about it? I am so sorry about it.are there fire protection specialists here?

[f81aa]

Hi taoxianwen123:

The Guidelines for Fire Protection in Chemical, Petrochemical, and Hydrocarbon Processing Facilities by the Center for Chemical Process Safety (American Institute of Chemical Engineers) states in section 7.4.1.2. Tanks and Reservoirs "Automatic refilling using an automatic float valve should be provided. A maximum refill time of 8-hours is recommended (NFPA 22)". Although this book mentions that NFPA 22 recommends 8 hours, the latter considers this time as mandatory by using "SHALL".

NFPA Standard 22 (version 2003, the most recent I have read) addresses elevated tanks on towers or building structures, water storage tanks that are at grade or below grade, and pressure tanks. This standard has been posted before in the Forum but I am uploading my copy for you and others to download. The link is

[link Point to another website Only the registered members can access]
The comments I am about to make are based on that year edition.

Chapter 13 Pipe Connections and Fittings, section 13.4 Filling, clause 13.4.1.3 states that "the bypass shall be sized to fill the tank in 8 hours". This Bypass around Check Valve is required for the filling pipe where the tank is to be filled from the fire protection system under city or fire-pump pressure.

And clause 13.4.2.1 requires that "when the tank is to be filled by a special filling pump, the pump and connections shall be of such size that the tank can be filled in 8 hours".

It can be seen that both cases are 8 hours, in agreement with the Guidelines for Fire Protection book.

When you get to browse NFPA 22, you will come across section 7.2.9 Water Filling Supply, clause 7.2.9.1 which indicates that "the filling supply or pump shall be reliable and shall be capable of replenishing the water that is required to be maintained in the tank with the required air pressure restored in not more than 4 hours". I do not think that this is related to your needs given that this requirement applies to pressure tanks which shall be permitted to be used for limited private fire protection services, such as those covered by the following NFPA standards:

(1) NFPA 13, Standard for the Installation of Sprinkler Systems
(2) NFPA 14, Standard for the Installation of Standpipe and Hose Systems
(3) NFPA 15, Standard for Water Spray Fixed Systems for Fire Protection

And pressure tanks shall not be used for any other purpose.

Finally, many years ago I read some guidelines of the INDUSTRIAL RISK INSURERS related to fire protection design. I recall that there was a requirement for replenishing the firewater spent at a rate of 50% the design discharge rate of the system, the worst case scenario discharge rate. Sorry I can not give you more details. I know I had a copy but I could not find it. That is why i took me some time to give you a hand.

I hope I could help you and I invite other members to make comments.

Regards

[Nabilia]

Here are the standards that f81aa mentioned for pressure tanks if anyone needs them plus a fire protection handbook...

NFPA 13-2010 Standard for the Installation of Sprinkler Systems.pdf

[link Point to another website Only the registered members can access]
NFPA 14 2010 Standard for the Installation of Standpipe and Hose Systems.pdf

[link Point to another website Only the registered members can access]
NFPA 15 2007 Water Spray Fixed Systems for Fire Protection 71pgs.pdf

[link Point to another website Only the registered members can access]
Industrial Fire Protection Handbook.pdf

[link Point to another website Only the registered members can access]

[taoxianwen123]

thanks f81aa & Nabilia .
but the refilling time of 8 hours is too tight,normally, the refilling time is based on the time interval that another fire happens again,do you think another fire will happen in 8 hours? and NFPA 22 is a standard for water tanks for "private fire protection".what is the meaning of private fire protection?Is it suitable for oil & gas plants and oil refineries?normally, thousands of cubic meters water shall be used each time in plants, if refilling time is 8 hours, then the water make-up capacity shall be at least serval hundreds of cubic meters per hour, then it will increase the treatment capacity of a source water treatment plant(in our projects, normally a source water treatment plant shall be built close to the river to supply filtered water for oil&gas plants).and it will increase the direct cost of a project.
I remember that for buildings in large communities,the refilling time is 48h, these data come from the analysis of the time interval that another fire happens again.
anyone others has different ideas?pls tell me.thanks a lot.

[Nabilia]

I have been at several facilities that had their fire water tank for first service, but had a back-up system where they could switch their water source from a containment pond on their site.

[f81aa]

Hi taoxianwen123:

You mentioned some points that I have not had time to address.

What is the meaning of "private fire protection"? I could not find it but I found some definitions (NFPA Glossary of Terms) related to phrases which include the word "private" and I am sharing them.

I hope you conclude that private fire protection is what is built on private property to detect, control and extinguish fires. Properly designed, It is suitable to protect oil & gas plants, oil refineries, private universities, nursing homes, theaters, etc. The point here is that it is built on private property, with private funds.

Having said that, if private fire protection can not count on public waterworks for a reliable supply and there is a need for storing water, different options will have to be assessed as well as many design guides will be consulted.

Major oil and chemical companies have their own standards. Same comment applies to major engineering firms. I am not saying that NFPA 22 should be used. I bet that you can think of other sources of information that fit better your needs; however, the post was started with the question "how long it required to refill the fire water tanks after a fire"? and NFPA 22 popped in my mind.

NFPA 22 is a widely known standard in the U.S. and the NFPA is recognized worldwide. Once it has been decided to use this standard for designing elevated tanks on towers or building structures, water storage tanks that are at grade or below grade, and pressure tanks, it does not matter what kind of property will be protected. Properly designed, it will be suitable to protect oil & gas plants, oil refineries, private universities, nursing homes, theaters, etc.

You have concerns related to water treatment. According to my experience, oil & gas plants/oil refineries, firewater is raw water, maybe with some minor treatment. It is not drinking water or boiler feedwater. I agree that water has to be treated for some uses. Unless, the quality of firewater is too bad or there are some requirements (Government, company policies, etc.) that I do not know, I see no need for special treatment.

I checked the water quality requirements in the NFPA standards that use water for protection. This is what I found:

NFPA 13 (2010), 23.1.5 Water Supply Treatment: Water supplies and environmental conditions shall be evaluated for the existence of microbes and conditions that contribute to microbiologically influenced corrosion (MIC). Where conditions are found that contribute to MIC, the owner(s) shall to treat the system using one of the 4 methods given in that standard. Water supplies and environmental conditions shall be evaluated for onditions that contribute to unusual corrosive properties. Where conditions are found that contribute to unusual corrosive properties, the owner(s) shall notify the sprinkler system installer and a plan shall be developed to treat the system using one of the 4 methods given in that standard.

NFPA 11 (2010), 4.2.1.1 Quality: The water supply to foam systems shall be permitted to be hard or soft, fresh or salt, but shall be of a quality such that adverse effects on foam formation or foam stability do not occur. No corrosion inhibitors, emulsion breaking chemicals, or any other additives shall be present without prior consultation with the foam concentrate supplier.

NFPA 16 (2007), 6.1 Water Quality: Water supplied to foam-water systems shall be compatible with the foam concentrate to be used. Water that contains solids likely to clog orifices in discharge devices but that is otherwise acceptable for making foam shall be permitted to be used after passing through line strainers.

NFPA 24 (2002), 5.8 Penstocks, Flumes, Rivers, Lakes, or Reservoirs: Water supply connections from penstocks, flumes, rivers, lakes, or reservoirs shall be arranged to avoid mud and sediment and shall be provided with approved, double, removable screens or approved strainers installed in an approved manner.

I found no special requirements for water quality in NFPA 14 (2007), NFPA 20 (2010) and NFPA 22 (2003). I hope I did not miss them. Same comment for NFPA 15 (2007); however, we know strainers are needed to avoid the plugging of nozzles.

Only NFPA 13 addresses corrosion in some detail. Notice that some of the methods proposed to control corrosion could be destructive for the foam concentrates (NFPA 11).

Let's discuss about the refilling time. I do not know if 8 hours is to tight. It is just the requirement of NFPA 22, mandatory if the standard will be used for design. Otherwise, it is just a reference.

I disagree that the refilling time is based on the time interval that another fire happens again. How can I know if another fire will happen in 8 hours or any other time, say 48 hours? How can anybody know this? Maybe it is based on statistics. If so, I hope they are related to the oil and chemical industries.

Say that the worst scenario fire ocurred and no water is left. I would hope to have my fire protection system available as soon as possible. Even if the plant shut down, there will be maintenance crews removing debris and trying to get the plant back on business. We know that fires occur during those activities.

I have a hard time seeing the refilling time of 48h (large communities) as a reference for oil&gas plants. I believe that most of the time they are not comparable.

Finally, I totally agree with Nabilia's post #6. I also have that experience. A backup system is needed and it will help you in choosing a more flexible amount of time for refilling.

Well, I see this Forum as a means for sharing experience and ideas. Other members are welcome to contribute.

[f81aa]

Sorry, I forgot the attachment.

[taoxianwen123]

thanks f81aa very much.I appreciate you spending so much time for giving me a hand.
in the handbook "fire fighting pumping systems at industrial facilities" which is uploaded in this forum,page 32,about the fire water storage tanks,it says "Storage tanks should have a means of automatic refill once a present low level has been reached. A refill time of not more than 24hours is recommended. Low level alarms to protect the pumping unit should be provided.
so, there are lots of diffefences in different handbooks or standards.I am wondering.

[Nabilia]

Thank you for your excellent and extensive answer f81aa, please check your attachment link, only the thumbnail is showing up.

[taoxianwen123]

about the back-up system,plant water like cooling water & desalt wash water can be used for back-up water,but it is very small comparing to the fire water.our plant water just 1000m3 can be used each time, and no cooling water system.
the source water treatment plant also can supply water at the same time if the fire happens in gas&oil plant,but it should also need time to treat, and it's treatment capacity is 4000m3/d, our fire water required capacity is 4000m3 each time, it means after a fire, it need one day to refill my fire water tanks, if 8 hours is required, then the capacity of my source water treatment plant shall be increased, and my water supply pipeline which connects source water treatment plant with gas &oil plant shall also be much greater.the whole direct cost of water supply system will increase,the design capacity of water pipeline shall be determined by the fire water supplying rather than the normal plant water supplying.this my misgivings.

[f81aa]

Hi taoxianwen123:

Thanks for your reference to "Fire fighting pumping systems at industrial facilities". I browsed that book but I missed the comment. Nice to know it since the refilling time is a value that I do not come across too often.

If you can not get a "solid" value (one nobody can dispute) when the deadline arrives, I suggest you to discuss it with your colleagues, take a decision, support it in written form and maybe, have it approved by the Authority Having Jurisdiction.

Nabilia, thanks. I hope that the "digital glue" (being more careful) I will use this time works better.

Please download from

[link Point to another website Only the registered members can access]
I am glad that both have found useful my comments. Thank you

Regards