Standard Steam Coils

Materials and Specifications

FINS

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 sinewave in a staggered tube pattern to meet performance requirements. Collars will hold fin spacing at the specified density and cover the entire tube surface. Aluminum properties are to be Alloy 1100 per ASTM B209, with O (soft) temper; copper is to be Alloy 11000 per ASTM B152-06 with soft (anneal) temper. Fins are to be free of oils and oxidations.

TUBES

Tubes and return bends are to 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 for maximum heat transfer. Minimum wall thickness: .025 for performance longevity.

HEADERS

Headers are constructed of seamless UNS C12200, Type L copper material sized to match specified connection size. Headers for steam distributing coils shall have die-formed end caps brazed on the inside of the headers. Headers for standard steam coils shall have finished integral spin-closed ends. All end closures are designed to withstand test pressure.

CONNECTIONS

Connection material can be copper, steel, or red brass pipe. The type of connection is to be sweat type, MPT or FPT, grooved, or flanged as required. Connections will be sized to accommodate supply steam and condensate loads. Steam distributing coil connection locations shall be such that steam is distributed adequately among all tubes, and that condensate is removed from all tubes to insure freeze protection.

CASING

Coil casing material shall be 16-gauge, G90 galvanized steel. Heavier gauge and optional material casings are available as required to meet specifications.  All tube sheet holes are to be oversized to allow for free thermal expansion and contraction of tubes during operation. 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.

PRESSURE TESTING

Coils shall be tested at 550 PSIG using dry nitrogen, submerged underwater. Dual-operator verification shall determine that all coils are leak-free.

CERTIFICATION

All steam coils are to be AHRI performance certified and bear the AHRI symbol. Coils outside the scope of AHRI’s standard rating conditions or the manufacturer’s certification program will be acceptable since the manufacturer is a current member of the AHRI coil certification program, and all coils will be rated in accordance with AHRI Standard 410.