Installation Guidance for Boiler Safety Relief Valves

by Newgram

Considerations when sizing of relief valves for boiler system

    • 2 or more safety relief valves should be provided on boiler/s with heating surface greater than 50 m2 (500 ft2); otherwise comply with local regulation or adhered to international guideline/standard whichever more stringent.
    • Safety relief valves should be sized to operate up to >6% of the maximum allowable working pressure for high pressure boiler.
    • Isolation valve should not be installed on the relief valves.

Example: Maximum working pressure of the boiler system with heating surface of 60 m2 is 120 barg.

Safety relief valve to operate would be 120 barg + (6% x 120) barg = 127barg.

The second safety relief valve to operate should be set at the maximum working pressure of 120 barg.

Boiler system integrated super heaters

    • Safety relief valves for the boiler should be designed to provide relieving capacity of up to 75% of the relieving capacity (in kg/hr) of the boiler system.
    • Safety relief valves for the super heaters should be designed to provide relieving capacity of up to 25% of the relieving capacity (in kg/hr) of the boiler system.

Independently fired super heaters

The relieving capacity for the safety valves should be based on 2.7 Kg/0.1m2 of heating surface.

Disclaimer

Information provided in this article are provided “as is” without warranty of any kind, either express or implied, including without limitation warranties of merchantability, fitness for a particular purpose and non-infringement. The author provides, with reasonable effort, accurate and up-to-date information in this article. It does not, however, make any warranties or representations as to its accuracy or completeness. It periodically adds, changes, improves or updates the information and documents in this article without notice. The author assumes no liability or responsibility for any errors or omissions in the content of its article. You are using the article at your own risk. Under no circumstances shall the author or any other party involved in creating, producing or delivering the contents of this article be liable to you or any other person for any direct, indirect, special, incidental or consequential damages arising from your access to, or use of, this article

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