Security Chimneys


Secure Seal® SS, SSD, SSID, and Flex
Quality and Dependability

The Secure Seal flue is manufactured from either 316L or 29-4C, a super-ferritic stainless steel designed for extreme resistance to chloride ion pitting, crevice corrosion and stress corrosion cracking, as well as general corrosion in oxidizing and moderately reducing environments. 29-4C and 316L are the ideal choice for withstanding the harmful effects of corrosive condensates created by partially or fully condensing high-efficiency natural gas and propane-fired heating appliances.

The Canadian Gas Research Institute found that test results proved 29-4C to be one of the two “most corrosion-resistant alloys of 20 candidate stainless steels evaluated for resistance to chloride-induced corrosion in condensing and partially condensing gas-fired appliances.”

Stringent Standards for Quality Assurance

To guarantee a perfect fit every time and to avoid built-in stress points or weak areas, tube ends are formed under stringent guidelines and held to exacting standards.

The casing (outer tube on Secure Seal SSD/SSID) is manufactured from type 441 stainless steel to provide long-lasting performance and stability when exposed to the outdoors.

The air space between the flue and casing is 1″ on SSD and 2″ insulated on SSID, providing close clearances to combustibles, reasonable outside dimensions and an additional heat shield or margin of safety where needed.

Built to Last

Secure Seal features a smooth weld seam inside and out, which is completely shielded during the welding process. Contamination or molecular changes in the weld seam are avoided and no fillers are used in the welding process.

The Secure Seal double-wall system is fully interchangeable with our Secure Seal single-wall system. Both have been conformed to UL1738 and certified to ULC-S636 safety standards. When installed according to Security Chimneys’installation instructions, Secure Seal meets all test requirements for horizontal and vertical, interior or exterior installations. SSID features the same construction as SSD, but with 2″ air space filled with mineral wool insulation.

  • Single and double wall for use with Categories I, II, III and IV gas-fired appliances, high-efficiency gas boilers, furnaces, booster heaters, pool heaters, water heaters, unit heaters or tankless water heaters
  • Listed as Type BH gas vent systems for appliances having a rated operating flue temperature of 480°F
  • Type L-Vent (SSD only) for venting listed SAS or oil fired appliances certified with Type L low temperature venting system
  • Systems are interchangeable; you can go from a single to double-wall with the use of an adapter
  • Laser butt-welding reinforces strength and prevents leakage while increasing durability and reliability
  • Flex features a smooth inner wall that provides for no output reduction, while supporting system’s overall strength
  • Built-in draw latches provide quick and easy tool-free assembly and disassembly, requiring less time on the job site
  • Viton-seals more resistant than silicone against chemicals such as sulfiric acid often found in condensate
  • Standard adjustable vent length provides vertical or horizontal adjustment for easy system pitching
  • 29-4C® stainless steel resists the extreme corrosive environments found in condensing boilers, assuring trouble-free operation and longer product life
  • Flex made from super-ferritic stainless steel, providing protection against chloride ion pitting and corrosion.
  • Tested and listed to UL-1738 and ULC-S636
  • 15-year warranty

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SSD – Vertical installationSS – Vertical Installation
SSD - Vertical installationSS - Vertical Installation