Section R20-5-415. Boiler Blowdown, Blowoff Equipment and Drains

A.      Except as provided in this Section, an owner or user of blow- down and blowoff equipment shall comply with the National Board Rules and Recommendations for the Design and Con- struction of Boiler Blowoff Systems, 1991 Edition, incorpo- rated by reference. This incorporation does not include any

later amendments or editions of the incorporated material. A copy of this referenced material is available for review at the Industrial Commission of Arizona, 800 W. Washington Street, Phoenix, AZ 85007 and may be obtained from the National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Avenue, Columbus, OH 43229-1183 or at http://www.nation- alboard.org/.

B.       Blowdown from a boiler is a hazard to life and property.

C.      Blowdown from a boiler shall pass through blowdown equip- ment that reduces pressure and temperature to levels not exceeding 5 p.s.i.g. and 140° F.

D.      The thickness of a blowdown vessel shall be at least 3/16”.

E.       All blowdown equipment shall be fitted with openings that allow cleaning and inspection of the equipment.

F.       Blowdown separators may be used with boilers instead of boiler blowdown tanks, provided that blowdown separators are operated with a temperature gauge and water cooler to pre- vent drain water temperature from exceeding 140° F.

G.      In addition to the requirements of subsections (A) through (F), the following requirements apply to blowdown piping, valves and drains for power boilers: Each power boiler and high tem- perature water boiler shall be installed and maintained accord- ing to ASME Code, Section 1 and B31.1, incorporated by reference in R20-5-404, at the time of installation.

H.      In addition to the requirements of subsections (A) through (F), the following requirements apply to bottom blowdown or drain valves for heating boilers and hot water heaters:

1.        A hot water heating boiler or hot water heater shall have a bottom blowdown or drain pipe connection fitted with a valve or cock connected with the lowest available water space with the minimum size of blowdown piping and valves as required by ASME Code, Section IV, incorpo- rated by reference, in R20-5-404(A).

2.        Discharge outlets of blowdown pipes, safety valves and other piping shall be located and structurally supported to prevent injury to individuals.

Historical Note

Repealed effective April 12, 1979 (Supp. 79-2). New

Section adopted effective April 9, 1992 (Supp. 92-2). R20-5-415 recodified from R4-13-415 (Supp. 95-1). Amended effective October 9, 1998 (Supp. 98-4). Amended by final rulemaking at 15 A.A.R. 1496, effec- tive August 18, 2009 (Supp. 09-3).