• CTSO-C20a Combustion Heaters and Accessories.pdf
• BS EN 1092-1-2007 Flanges and their joints - Circular flanges for pipes valves fittings and accessories PN designated - Part 1 Steel flanges.pdf
• BS EN 1092-2-1997 Flanges and their joints. Circular flanges for pipes valves fittings and accessories PN designated. Cast iron flanges.pdf