1、I INCH-POUND I A-A- 50543 September 30. 1993 SUPERSEDING 20 July 1953 MIL-H-18551C COMMERCIAL ITEM DESCRIPTION HEATERS, CONVECTION, STEAM OR HOT WATER This Commercial Item Description (CID) is approved by the Commissioner, Federal Supply Service, General Services Administration, for the use of all F
2、ederal agencies. 1. Abstract. This CID covers coil or cast finned-tube heaters (convectors) of the natural-air-circulation type, operated with steam of hot water to supply heated air in individual rooms of residences, offices, etc. Types, classes, styles, models and sizes are as follows: - - A-A-505
3、43 W 9999974 0155741 913 Type I - Nonferrous heating element. . Type II - Ferrous heating element. Class 1 - Nonrecessed. O Class 2 - Recessed. Style A - Floor-mounted (free-standing). Style B - Wall-mounted. Model F - Front air outlet. Model T - Top air outlet. Model S - Side, front, and top air ou
4、tlet, perforated metal construction. Size 14 - Overall height of 14 inches (355.60 millimeters (mm). Size 16 - Overall height of 16 inches (406.40 mm). Size 18 - Overall height of 18 inches (457.20 mm). Size 20 - Overall height of 20 inches (508.00 mm). Size 22 - Overall height of 22 inches (558.50
5、mm). IBeneficial comments (recommendations, additions, deletions) and any pertinent1 Idata which may be of use in improving this document should be addressed to: I ICommanding Officer (Code 156), Naval Construction Battalion Center, I Il000 23rd Avenue, Port Hueneme, CA 93043-4301. I FSC 4520 DISTRI
6、BUTION STATEMENT A. Approved for public release; distribution is _ unlimited, Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_ _- -_- A-A-50543 E 1199974 0155742 5T m A-A- 50543 Size 24 - Overall height of 24 inches (609.60 mm). Size 26 - Overall he
7、ight of 26 inches (660.40 mm). Size 28 - Overall height of 28 inches (711.20 mm). Size 30 - Overall height of 30 inches (762.00 mm). Size 32 - Overall height of 32 inches (812.80 mm). I 2. Salient characteristics. 2.1 DeSCriDtiOn. The heaters, convection, steam or hot water (referred to herein as “h
8、eaters“) shall be a self-contained, factory-assembled unit, consisting of tubes, expanded surfaces (fins), headers, when required, and an enclosure. The enclosure shall be of either the cabinet or section type (see 2.3.5). The heating element shall have provisions for connections to steam or hot-wat
9、er piping, as specified (see 6.1). 2.2 CaDacitv. The heater shall have a capacity in British thermal units per hour (Btu/hr) (watt) not less than that specified when operated with steam or hot water at the temperature and pressure specified (see 6.1). The capacity shall be based on an entering air t
10、emperature of 65 degrees Fahrenheit (OF) (18.35 degrees Celsius (OC). Unless otherwise specified (see 6.1), the maximum surface temperature of the enclosure shall be 175F (79.44OC). 2.3 Design and construction. The heaters shall be designed to withstand, without deformation, leakage, or damage, a mi
11、nimum hydrostatic test pressure of 100 pounds per square inch gage (psig) (689.47 kilopascals (kPa) (gage). The design shall be such as to prevent conditions which may be hazardous to personnel or deleterious to equipment. All necessary brackets and fasteners for mounting style B heaters shall be fu
12、rnished. Unless otherwise specified (see 6.1), the heaters shall be tapped at opposite ends. 2.3.1 Heating element. The heating element shall consist of headers, when required, and of expanded-metal (finned) tubes. 2.3.2 Tubes and fins. Tubes and fins shall be suitable for the heating medium and con
13、ditions as specified herein. Tubes shall be considered a primary heating surface and shall be copper, brass, manganese, steel, or aluminum. Fins shall be considered a secondary heating surface and shall be copper, steel, or aluminum. The fins shall be continuously bonded to the tubes to insure a tig
14、ht, rigid, metal-to-metal contact under specified operating conditions. The fins shall have a uniformpitch, be in a plane perpendicular to the centerline of the pipe, and have smooth surfaces, free from wrinkles or kinks, except that die-formed fins curved toincrease turbulence will be acceptable. O
15、rifices or baffle plates of proper size shall be provided when required to insure uniform distribution of the heating medium to each tube. minimize expansion and contraction stresses. Tubes shall be arranged to 2.3.3 Headers. Headers, when required, shall be cast iron, cast brass, steel tubing, stee
16、l pipe, steel plate, or copper tubing. Finned tubes shall be mechanically bonded to cast iron, steel tube, or copper tube headers but may be brazed or welded to steel pipe or steel plate headers. When headers are used on hot water systems the water velocity shall be not less than 1 foot per second (
17、0.30 meter per second) through the finned tubes. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_-_ -I_- - A-A-50543 m 9999974 0355743 79b A-A- 50543 2.3.4 Air chamber and ventinv device. the highest point of the heating element shall be provided
18、with an air chamber and with a manual venting device operable without removal of any part of the heater. When specified (see 6.1), an automatic venting device shall be furnished, When the heating medium is not water, 2.3.5 Enclosure. steel cabinet or section type enclosure. by configuration design,
19、bracing, or reinforcing. Horizontal tubes shall have a pitch with respect to the enclosure for proper drainage. Trappings of condensate in steam systems or air in hot-water systems shall be avoided. Unless otherwise specified (see 6.1), dimensions other than the height (see i) shall be at the manufa
20、cturers option. When specified (see 6.1), the air-outlet opening shall be equipped with a readily adjustable damper. The heating element shall be completely enclosed in a sheet Proper rigidity shall be accomplished 2.3.5.1 Cabinet tme. The cabinet type enclosure shall be sheet metal not less than 18
21、 gage (0.0478-inch (1.21 mm) nominal thickness) for top and front and not less than 20 gage (0.0359-inch (0.91 mm) nominal thickness) for sides and back. When galvanized, the nominal thickness shall be 0.050-inch (12.70 mm) and 0.0375-inch (0.95 mm), respectively. to allow access to the heating elem
22、ent. The front panel shall be readily removable 2.3.5.2 Section tvpe. thickness of not less than 20 gage (0.0359-inch (0.91 mm) nominal) and so formed as to increase the strength of the material. The section shall be bonded to the tube or primary surface and shaped to form a flue. proper configurati
23、on to prevent accumulation of dirt and other foreign matter. Inlet and outlet air grilles and fin spacing shall be designed for proper air velocity. The section type enclosure shall be metal having a The enclosure shall have 2.3.5.3 Model F. T. and S. Model F and model T shall be provided at the bot
24、tom of the enclosure with air inlet openings that need not be grilled, and with a grilled air outlet at or near the top. with a perforated metal housing covering the front, top, and sides. Model S enclosures shall be provided 2.4 Commercial manual. When specified (see 6.1), a commercial off-the-shel
25、f manual with parts list shall be provided for each convection heater. 3. Reaulatory reauirements. The offerer/contractor is encouraged to use recovered materials in accordance with Public Law 94-580 to the maximum extent practical. 4. ualitv assurance. 4.1 Contractor certification. The contractor s
26、hall certify and maintain substantiating evidence that the product offered meets the salient characteristics of this CID and that the product conforms to the producers own drawings, specifications, standards, and quality assurance practices. The Government reserves the right to require proof of such
27、 conformance prior to first delivery and thereafter as may be otherwise provided for under the provisions of the contract. 4.2 Metric Rroducts. Products manufactured to metric dimensions will be considered on an equal basis with those manufactured using inch-pound units, 3 Provided by IHSNot for Res
28、aleNo reproduction or networking permitted without license from IHS-,-,- _ _ A-A-50543 9999974 0355744 622 W A-A-50543 provided they fall within tolerances specified using conversion tables contained in the latest revision of FED-STD-376, and all other requirements of this document are met. If a pro
29、duct is manufactured to metric dimensions and those dimensions exceed the tolerances specified in the inch-pound units, a request should be made to the specification preparing activity for changes to this document, 5. Packaging. - Unless otherwise specified in the contract or order (see 6.1), the pr
30、eservation, packing, and marking shall be in accordance with ASTM D3951. 6. Notes. 6.1 Ordering data. Acquisition documents should specify the following: a. b. d. C. e. f. g. h. i. Title, number, and date of this CID. Type, class, style, model, and size of heater required (see 1). Whether a steam or
31、 hot water system shall be used (see 2.1). Capacity in Btu/hr (watt) and values of steam pressure (psig) (kPa (gage), or entering water temperature (OF) (OC) and water pressure (psig) (kPa (gage), as applicable; and enclosure surface temperature, if other than as specified (see 2.2). When tapping lo
32、cation is other than as specified (see 2.3). When an automatic venting device is required (see 2.3.4). Maximum enclosure dimensions and adjustable damper, when required (see 2.3.5). When commercial manual shall be provided (see 2.4). When preservation, packaging, packing, and marking is to be other
33、than as specified (see 5). 6.2 Source of documents. available from Standardization Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094. Copies of Federal and military documents are 6.3 Source for non-Government association documents. ASTM D3951 is available from ASTM,
34、1916 Race Street, Philadelphia, PA 19103. 6.4 CID-based part identification numbers. The following part identification numbering procedure is for Government purposes and does not constitute a requirement for the contractor. A - 50543 - X - X - X - X - X I l I I I .I I- I I IlII I I IlII I I III I I
35、II I I I I I I I I I I I Air venting and damper options Tapping and heater material options Size and steam or hot water Style and model code number Type and class code number CID number Designates a CID 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,
36、-,- -_- - A-A-50543 a 9999974 OL557r15 5b9 a A-A- 50543 6.4.1 Twe and class. single number (see table I). The type and class of heater units are identified by a TABLE I, TyDe and class. Class I Class I Class 2 I TvDe Nonrecessed Recessed I I I I I I Type I - Nonferrous heating element I Type II - Fe
37、rrous heating element 1 3 I 2 I 4 I 6.4.2 Style and model. single number (see Table 11). The style and model of heater units are identified by a TABLE II. Style and model. I I Model F - Front air outlet 1 2 I Model T - Top air outlet 3 4 I Model S - Side, front, and top 5 6 I outlet (perforated meta
38、l I construction) I. I Model Style A Style B I Model Floor-mounted Wall-mounted I I I I 6.4.3 Size and steam or hot water. heater units are identified by a single letter (see table III). The size and heating medium option of TABLE III. Size and heating medium. Heating Medium Size Steam Hot water I I
39、 l I Size 16 overall height of 16 inches (406.40 mm) B M I Size 18 overall height of 18 inches (457.20 mm) C N I Size 20 overall height of 20 inches (508.00 nun) D P I Size 22 overall height of 22 inches (558.80 mm) E R I Size 24 overall height of 24 inches (609.60 mm) F S I Size 26 overall height o
40、f 26 inches (660.40 mm) G T I Size 28 overall height of 28 inches (711.20 mm) H U I Size 30 overall height of 30 inches (762.00 mm) J V I Size 32 overall height of 32 inches (812.80 mm). K X - A L I Size 14 overall height of 14 inches (355.60 mm) I I 6.4.4 Tapping and header material. heater units a
41、re identified by a single letter (see table IV). The tapping location and header material of 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-50543 TABLE IV, Tapping and header material. I Tapping Location Header Material Both right Both left Op
42、posite ends I I I Cast Iron Cast Brass Steel Tubing Steel Pipe Steel Plate Copper Tubing I I I I I I I I N I P I R I S I T I U I 6.4.5 heater units are identified by a single number (see table V). Air venting and damper option. The air venting and damper option of TABLE V. Air venting and damper. Da
43、mper I Without damper I Air Venting With damper I I I I Manual Air venting I Automatic air venting 1 3 I 2 I 4 I O 6.4.6 Supersession data. This CID replaces military specification MIL-H-18551C dated 20 July 1983. 6.5 Classification cross reference. Classifications used in this CID (see 1) are ident
44、ical to those found in the superseded military specification, MIL-H-18551C. MILITARY INTERESTS: CIVIL AGENCY COORDINATING ACTIVITY: Custodians GSA - FSS Navy - YD1 Air Force - 99 Review Activities PREPARING ACTIVITY: Navy - YD1 (Project 4520-0340) Army - CE Navy - MC DU - CS 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
