ASME Sect. 1 Code Safety Valve mounting

[Jedediah]

Hello,

I have a Steam Generator with a heating surface greater than 500sq.ft. ASME Sect. 1 Code requires two safety valves for over pressure protection. Currently the boiler only has one safety for full relieving capacity, however I need to get this boiler in compliance with the Code. So I plan to either add a new nozzle and use the existing nozzle to size two new safety valves as a combined relief capacity. Or another option is to just use the existing 3” nozzle and use a “Y” base per Section PG-71.1 which is allowed to be used beneath two safety valves.

My question is, following PG-71.2 it states a required maximum face to face dimension of a intervening fitting or pipe of the same size tee fitting if used between the boiler nozzle and safety valve. Does the face to face dimension requirement apply to the “Y” base face to face dimension as well if used? Which for a 3” tee fitting dimension is around 11” per ASME.

 

[The Obturator]

Reading PG-71.2 straight after 71.1 I doubt very much if it applies to the Y-Base. 71.2 is essentially telling you not have any other laterals etc. The allowed use of a Y-Base is very clear.

*** Per ISO-4126, the generic term 'Safety Valve' is used regardless of application or design ***

*** 'Pressure-relief Valve' is the equivalent ASME/API term ***