Fired Jacketed Steam Kettles. Fired jacketed steam kettles may be constructed
in accordance with ASME Code
, Section VIII, provided the following requirements
(a) Welded joints in contact with
products of combustion shall be of Type No. 1 of Table UW-12, ASME Code,
(b) When parts
subjected to pressure are made of carbon steel material, the minimum thickness
shall be one fourth (1/4) inch. The minimum thickness of stainless steel or
nonferrous pressure parts shall be as specified in the applicable part of ASME
Code, Section VIII, Subsection C.
(c) When in contact with products of
combustion, carbon steel material shall be pressure vessel quality and
austenitic stainless steel parts shall be either extra-low carbon or stabilized
(d) Structural grade carbon
steel shall not be used for any pressure part.
(e) The operating pressure of the jacket
shall not exceed 50 psig.
Vessels constructed under this rule shall be inspected by an authorized
inspector. Such vessels marked with the UM Symbol are not acceptable.
(g) No steam or water shall be withdrawn from
the jacket for use externally to the vessel.
(h) The capacity of the safety valve in
pounds of steam per hour shall be at least equal to the BTU rating of the
burner divided by one thousand (1000).
The jacket shall be equipped with the
following minimum appurtenances and controls.:
1. A pressure gauge;
2. A water gauge glass;
3. A separate connection, fitted with a check
valve and stop valve, for adding water to the jacket;
4. An automatic gas valve controlled by
pressure or temperature to maintain the steam pressure in the jacket below the
safety valve setting;
5. A low
water cutoff that will cut off the fuel to the burner if the water in the
jacket drops below the lowest permissible water level as established by the
6. A safety pilot
control that will cut off the fuel to both the main burner and the pilot burner
in case of pilot flame failure.