CSA 4.4:2015 pdf download.Relief valves for hot water supply systems
4.2.4 The total area of any body flow passage, except the orifice, shall not be less than the difference between the inlet connection area and the thermostatic element area. In determining this area, any area in a corner which would not be included in a circle 3/16 in (4.8 mm) in diameter with its insides adjacent to the sides of the flow area shall not be included.
4.2.5 The smallest cross-sectional dimension of any flow way shall not be less than 3/16 in (4.8 mm) except:
a) the flow way between the relief valve body wall and the valve disc holder shall not be less than 1/16 in (1.6 mm) providing the minimum dimension of the flow area below the lip of the disc holder is at least 3/16 in (4.8 mm); and
b) the flow way between the walls of the orifice and any part of a temperature element extending through the orifice shall not be less than % in (3.2 mm). The minimum dimension between any part of a temperature element below the orifice, which is larger than that part extending through the orifice, and the lower edges of the orifice shall be 3/16 in (4.8 mm).
4.2.8 The body flow way between the seat and the discharge connection of pressure and T&P valves shall be constructed so that the bottom of the flow way and inside surface of the discharge pipe are at least 3/32 in (2.4 mm) below the face of the seat or the lowest part of the relief valve disc holder, whichever is lower.
4.3 Bolts and screws
Threads of bolts, nuts, and screws used in the assembly of body parts or for installation of the device shall be in accordance with the Standard for Unified Inch Screw Threads (UN and UNR Thread Form),ANSI B1.1.
4.4 Adjustments
Relief valves covered by this Standard shall have no means for field adjustment of the temperature or pressure settings.
A pipe wrench or open-end wrench shall be utilized to apply the turning force. The turning force shall be applied to the wrench grip of the device or to the body of the device if a wrench grip is not provided.The measured torque specified in Table 2 shall be applied to the completely assembled device in fitting it into a tank or extra heavy piping of suitable size. Pipe thread lubricants and sealants shall not be used. After the force has been applied for 15 minutes, it shall be released, the device removed and examined for deformation or breakage, and then subjected to the leakage test(s) specified in Clauses 5.4, Leakage;6.4, Leakage; or 7.3, Leakage of Water; whichever is applicable.
There shall be no sign of rupture or mechanical dislocation of parts of the enclosure communicating with the atmosphere.CSA 4.4 pdf download.