[Code of Federal Regulations]
[Title 46, Volume 2]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR52.01-95]

[Page 128]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 52_POWER BOILERS--Table of Contents
 
                   Subpart 52.01_General Requirements
 
Sec. 52.01-95  Design (modifies PG-16 through PG-31 and PG-100).

    (a) Requirements. Boilers required to be designed to this part shall 
meet the requirements of PG-16 through PG-31 of the ASME Code except as 
noted otherwise in this section.
    (b) Superheater. (1) The design pressure of a superheater integral 
with the boiler shall not be less than the lowest setting of the drum 
safety valve.
    (2) Controls shall be provided to insure that the maximum 
temperature at the superheater outlets does not exceed the allowable 
temperature limit of the material used in the superheater outlet, in the 
steam piping, and in the associated machinery under all operating 
conditions including boiler overload. Controls need not be provided if 
the operating superheater characteristic is demonstrated to be such that 
the temperature limits of the material will not be exceeded. Visible and 
audible alarms indicating excessive superheat shall be provided in any 
installation in which the superheater outlet temperature exceeds 454 
[deg]C (850 [deg]F). The setting of the excessive superheat alarms must 
not exceed the maximum allowable temperature of the superheater outlet, 
which may be limited by the boiler design, the main steam piping design, 
or the temperature limits of other equipment subjected to the 
temperature of the steam.
    (3) Arrangement shall be made for venting and draining the 
superheater in order to permit steam circulation through the superheater 
when starting the boiler.
    (c) Economizer. The design pressure of an economizer integral with 
the boiler and connected to the boiler drum without intervening stop 
valves shall be at least equal to 110 percent of the highest setting of 
the safety valves on the drum.
    (d) Brazed boiler steam air heaters. Boiler steam air heaters 
utilizing brazed construction are permitted at temperature not exceeding 
525 [deg]F. Refer to Sec. 56.30-30(b)(1) of this subchapter for 
applicable requirements.
    (e) Stresses. (Modifies PG-22). The stresses due to hydrostatic head 
shall be taken into account in determining the minimum thickness of the 
shell or head of any boiler pressure part unless noted otherwise. 
Additional stresses, imposed by effects other than internal pressure or 
static head, which increase the average stress over substantial sections 
of the shell or head by more than 10 percent of the allowable stress 
shall be taken into account. These effects include the weight of the 
vessel and its contents, method of support, impact loads, superimposed 
loads, localized stresses due to the reactions of supports, stresses due 
to temperature gradients and dynamic effects.
    (f) Cylindrical components under internal pressure. (Modifies PG-
27.) The minimum required thickness and maximum allowable working 
pressure of boiler piping, tubes, drums and headers shall be as required 
by the formula in PG-27 of the ASME Code except that threaded boiler 
tubes are not permitted.

[CGFR 68-82, 33 FR 18815, Dec. 18, 1968, as amended by CGD 81-79, 50 FR 
9432, Mar. 8, 1985]