CSA B51:19 Boiler, pressure vessel, and pressure piping code.
6.3.5 Boiler inspection openings
When manholes are specified or required for a boiler, they shall be at least 406 mm (16 in) in inside diameter or oval with inside dimensions of 305 x 406 mm (12 x 16 in).
The loadings to be considered in designing a boiler shall include, when necessary, those from
a) superimposed static reactions from the weight of attached equipment, such as motors, machinery, other vessels, piping, linings, and insulation;
b) cyclic and dynamic reactions due to pressure or thermal variations, or from equipment mounted on a vessel, and mechanical loadings,
c) temperature gradients and differential thermal expansion, and
d) test pressure and coincident static head acting during the test.
Note: Refer to Section VIII, Division 1, UG-22, of the ASME Code for interpretation.
6.4 Boiler outlet dampers
Outlet dampers on automatically fired boilers shall be interlocked to the burner control system so that the boilers cannot be fired unless the dampers are sufficiently open.
6.5 Blowoff vessels, systems, and devices
When the blowoff from a boiler having a working pressure exceeding 103 kPa (15 psi) is discharged into a sewer system, a registered blowoff vessel or other suitable registered device shall be placed between the boiler and sewer to reduce the temperature of the water entering the sewer system to 65 °C (150°F) or lower. Blowoff vessels shall be designed in accordance with Clause 7.5.
1) Temperature-limit contro! devices may be attached to the vessel or water discharge line to control the temperature at or below 65 °C (150°F).
2) Austenitic stainless steel used in water-wetted service is susceptible to stress-corrosion cracking and should not be used.
3) Other regulations or codes (such as building or plumbing codes) con require further restrictions, such as lower temperatures or pH level restrictions on water entering a sewer system.
Blowoff systems of a proprietary design that do not meet the requirements of Clause 18.104.22.168 or 22.214.171.124 shall be designed to meet the requirements of Clause 7.1. The design shall be submitted to the regulatory authority for registration before installation of the system.CSA B51 pdf download.