1 reply to this topic

[MacProcess]

Dear,

 

We have fuel gas fired heaer and heater has main fuel gas line and off gas line.

 

Off gas duty is about 10% of total heater duty.

 

Main fule gas and pilot gas lines have double UVs (Shut-off Valves) and vent UV valve.

 

However, Off gas line has only one UV and vent UV.

 

Do you know why off gas line has only one UV?

 

Is there any possiblility of explosion when off gas UV is failed to open when required?

 

Off gas is generated from process and mainly methane, ethane, and propane.

 

Thank you.

[AlertO]

Hi

 

This is a good notice. if we refer to standard like API (556), it states that 2 valves is series is required for isolating fuel gas (in this system, your off gas should be considered as well). 

Moreover, you may need to check that the the existing SIS function on your off-gass shall be according to the UV vavle on main fuel gas line.

 

Hope this may answer your query.