CSA C309-M90:2019 pdf download.Performance Requirements for Glass-Lined Storage Tanks for Household Hot Water Service
1.1 CSA C309-M90 applies to glass-lined storage tanks for household hot water service. Requi rements are given for base metal,construction, glass lining, cathodic protection, inspection, and testing.
1.2 This Standard covers glass-lined storage tanks at the point of manufacture, having 610 mm ( 24 in) inside diameter and less, with a max imum working pressure of 1034 kPa ( 150 psi) ，and subject to maximum input limitations as follows:
(a) electric--single element, 4500 W;
(b) electric--double element, 4500 W upper, 4500 W lower，flip flop circuit (alternate operation) ;
(c) oil-fired--2.84 L/h (0.75 US gal/h) or less; and
(d) gas-fired--less than 21 980 W ( 75 000 Btuh) .
1.3 The values given in SI (metric) units are the standard.The values given in parentheses are for information only.
2.1 Definitions
The following definitions apply in this Standard:Anode--a device that maintains the metal tank electrically negative in relation to the water in the tank
Burnoff--a defect resulting from the firing process that can be recognized by
(a) a complete lack of gloss; or
(b) a reddish-brown or black appearance of the lining over the affected area.
Calibrated magnetic thickness gauge--a magnetic thickness gauge that has been calibrated by checking it against a part of similar thickness, shape, and magnetic properties with a known thickness of nonmagnetic material, or using an equivalent method.
Cathodic protection--the condition that exists when a metal tank is maintained electrically negative in relation to the water it contains, sufficient to prevent corrosion of the base metal.
3.1 General
Glass-lined tanks shall effectively resist the chemical action of hot water as generally encountered in household hot water service,the water not being softened within the household upstream from the water heater.
3.2 Base Metal
The walls, heads, and other parts that are glass-lined shall be of iron or steel of a quality that is suitable for glass lining by the manufacturer's process and equipment, so that the tanks will consistently meet the requirements of this Standard.
3.3 Damage By Pressure
A hydrostatic pressure of 110% of the working pressure shall not cause any visible cracking in the glass on the inside surface of the tank.The required hydrostatic pressure shall be applied within 1 min and hela for 15 min, after which the tank shall be cut and examined for damage.
3.4 Fittings
The fittings shall be so designed and attached to the tank that repeated tightening and loosening of the connecting parts will not cause leakage around the tank fitting or fracture of the glass lining on the interior sur faces when tested in accordance with Clause 5.1. Where fittings involve threads or sharp edges that are normally free of glass, and are exposed to direct contact with water，the distance frqm such points to the nearest outside surface on the tank shall be at least 1-1/2 times the metal thickness in the body of the tank.Typical sections are shown in Figure 1.CSA C309-M90 pdf download.