Secondary surface (fins) shall be of the plate-fin design using aluminum or copper, with die-formed collars. Fin design to be flat, waffle, or sine-wave in a staggered tube pattern to meet performance requirements. Collars will hold fin spacing at specified density, and cover the entire tube surface. Fins are to be free of oils and oxidation.

Coil casing material shall be galvanized steel at a 16 gauge minimum. Heavier material, stainless steel, copper or aluminum casings are available as required.

Intermediate supports are required on all coils 50″ of finned length and longer. Coil casings on top and bottom of coils are to have double-flange construction, allowing for vertical stacking of coils.

Seamless copper tubes shall be mechanically expanded into plate aluminum or copper fins to form an everlasting bond between primary and secondary surfaces. Tubes are to be mechanically expanded into fins (secondary surface) for maximum heat transfer

Coils shall be tested at 550 psig using dry nitrogen, submerged under water. Dual-operator verification shall determine that all coils are leak-free. Steam coils are guaranteed up to a maximum 150 psig saturated steam supply pressures with appropriate wall thickness.