Posted by tom stanton on January 06, 2002 at 12:57:45:
In Reply to: economizer piping posted by rick ratliff on January 06, 2002 at 10:08:41:
Most installations will connect feedwater regulators, check and stop valves in the piping leading to the economizer inlet header. In this application, the regulator,check and stop would all be considered boiler external piping and fall under B31.1. I have, although, seen regulators, checks and stops connected to the outlet side of the economizer. In this case I still consider it B31.1 based on what the preamble in Section 1 states: "boiler external piping shall be considered as that piping which begins where the boiler proper terminates at: (a) the first circumferential joint for welding end connections or (b) the face of the first flange in bolted flanged connections or (c) the first threaded joint in that type of connection, and which extends up to and including the valve or valves required by this code. My experience with economizers have all been on large water tube and HRSG type boilers.