Pressure Relief Valve Piping 1

[TomFitz]

We have recently installed a hot water boiler (Unilux Bent Water Tube Boiler)
Input capacity: 18,000,000 BTU
Output: 15,300,000
power rating: 457 BHP
Operating Pressure: 29 PSIG
Operating Temperature: 200 deg. F.

I have the blow-down valve piped to a flash tank..
We have three Watts Pressure Relief Valves Series 174A-740
which I have piped individually to a floor drain.
(which I believe is OK since it is not classified as a power boiler)

I am told by the user (not the owner) that it is mandatory that these pressure relief valves be piped to the flash tank. (but show no documentation to this effect)..

Am I correct in piping them to floor drains?

Thanks for any response....

Tom

 

[spector]

Refer to local code. Ask the boiler ispector in you area to take a look.

I know of no such requirement. Usually SV escape piping need only be directed to a safe area. There are many other considerations too, but this is not one.

 

[smckennz]

Hi Tom
I have seen no regulations, but the obvious question is why pipe blowdowns to a flash tank but not safeties? Is the vent pipe large enough.
Are the drains rated for 200F.
While there is neither much steam hazard nor much of a pressure one (assuming decent sized drains) a consistent approach normally succeeds.
If it doesnt cost too much, pipe them to the flash tank.

It it is expensive, and regulations permit, threaten to remove the flash tank and put everything down the drain.

Cheers

Steve

 

[dugal]

I have seen many RV vent pipings going to floor drains. Not sure on the codes. Guess you could look at the worse case scenarios. What would be the environment of the room should one RV fully open and stay open?

Cio

 

[EGT01]

This is one area I have little experience but am interested to learn more. I assume we are talking about following requirements per ASME Sec I Power Boilers or ASME Sec IV Heating Boilers but sounds like you're making a case that Sec I does not apply.

I happen to find some excerpts from Sec IV (1998 edition) that might apply:

HG-701.6 Safety and Safety Relief Valve Discharge Piping

(b) The discharge from safety or safety relief valves shall be so arranged that there will be no danger of scalding attendants. The safety or safety relief valve discharge shall be piped away from the boiler to the point of discharge, and there shall be provisions made for properly draining the piping. The size and arrangement of discharge piping shall be independent of other discharge piping and shall be such that any pressure that may exist or develop will not reduce the relieving capacity of the relieving devices below that required to protect the boiler.

As previously suggested, check with someone who knows (and has a full set of) the codes. It would be interesting to know what you find out.

 

[LSThill]

Hi EGT01 (Chemical)

Please check 2001 ASME SECTION IV, Rules for Construction of Heating Boilers,

You may want to take the NBIC EXAM

Boiler Pressure Vessel Training course scheduled for May 16 - May 28, 2003. I am the course manager and am here to answer any questions that you might have. If you have not already, you may want to go to our website at

http://ccs.goivytech.net/boiler_pressure

for more details on the course and what books you will need to bring with you. There is also information regarding hotels. The instructors (Dan Willis and Allan Clark) will be staying at the Hampton Inn here in Terre Haute and we recommend that students stay there also, if possible. We have reserved a block of rooms, with a special room rate, for this course, should you decide to stay at the Hampton. Evening study sessions and access to instructors tends to be more convenient. Be sure to let your travel agency know to advise the Hampton Inn that you are in the Boiler Pressure class.

I will be sending you information on Terre Haute, In. Since Terre Haute does not have any direct commercial commuter flights, you will need to fly into Indianapolis and take a rental car to the hotel. Class will start on Sunday, February 16, at 1:00 at the Ivy Tech State College Airport Campus located at the Terre Haute International Airport, 501 S. Airport Street, Terre Haute, IN. Maps on our website will show hotel and campus locations.

Should any questions arise in the interim, please let me know.

Joseph P. Zinkovich, Manager
Ivy Tech State College
501 S. Airport Street
Terre Haute, IN 47803
812-298-2363
812-877-1184 - Fax

http://www.goivytech.net

Leonard@thill.biz

http://www.thill.biz

 

[deanc]

You must check local building codes. There may be restrictions for hot water to the drains.

 

[TomFitz]

Thank You "Y'all" for your responses..

The Boiler was installed in a Central Energy Plant on a Federal Government reservation,..therefore exempt from city and state requirements.. And, the existing floor drain is used by other existing tanks and equipment that are on a Hight Temp Hot Water system..
I would have put all the RV's to the flash tank, but with all other lines from two other HTHW generators going to it, there wasn't much room.. also having to go through 12" of concrete..
I have also contacted the people at WattsRegulator,.. and they agree that the floor drains would be OK..
Neverthelass, I will contact the state to see what they have to say...

Thanks Again
TomFitz

 

[spector]

As a federal site you are exempt from local regs, but your agency requires that you get your boilers inspected IAW local/state laws....Kinda a catch-22, huh? That means your local/state inspector can't enforce code, but he doesn't have to grant a certificate either...And your agency instruction requires you have that certificate. So, like I said before, contact your local/state boiler inspector and let him advise you. You will see that it's ok to direct the RV escape to a floor drain providing the piping is configured IAW ASME NBIC and local/state codes.

That aside, being exempt from local code is no reason to ignore such codes. Most codes have evolved from many years of hard learned experience and tend to be the minimum requirements.