Secondary surface (fins) are of the plate-fin design using aluminum or copper, with die-formed collars. The fin design is to be flat, waffle, or sine-wave in a staggered tube pattern to meet performance requirements.

Coil casing material shall be 16-gauge, G90 galvanized steel. Heavier gauge and stainless-steel casings are available as required to meet specifications. Intermediate tube supports are to be provided on all coils 50” and longer in fin length. Coil casings on top and bottom of coils are to have double-flanged construction, allowing for vertical stacking of coils.

Tubes and return bends shall be constructed from seamless UNS C12200 copper conforming to ASTM B75 and ASTM B743. Properties shall be O50 light annealed, with a maximum grain size of 0.040mm. Seamless tubes are to be mechanically expanded into plate fins to form an everlasting bond between primary and secondary surfaces.

Coils comprised of round tubes shall be tested at 550 PSIG using dry nitrogen while submerged underwater. Dual-operator verification determines that all coils are leak-free. Sectional and cleanable coils designed with removable sections shall be leak tested at two times the recommended operating pressure, or 150 PSIG.

Connection material can be copper, Schedule 40 steel, or red brass pipe. The type of connection is to be sweat type, MPT or FPT, grooved, or flanged as required.

Headers are constructed of seamless UNS C12200, Type L copper material sized to match specified connection size. Headers are to have finished integral spin-closed ends designed to withstand test pressure. 1/4” vents and drains are provided for al fluid coils unless specified otherwise.