SPIROsafe® Single Wall Specification

I. GENERAL
II. MATERIALS
III.CONSTRUCTION
IV. PERFORMANCE

I. GENERAL

A. All round supply, return and exhaust ductwork shall be SPIROsafe® as manufactured by Lindab, Inc (800) 797-7476 or approved equal. The duct system shall consist of fittings that are factory fitted with a sealing gasket and spiral duct which, when installed according to the manufacturer's instructions, will seal the duct joints without the use of duct sealer.

B. The contractor may, at his option, convert any or all rectangular ductwork to round provided that the project space limitations are properly addressed and that the overall system design static pressure not be exceeded.

II. MATERIALS

A. Unless otherwise noted, all duct and fittings shall be G-90 galvanized steel in accordance with ASTM A-653 and A-924.

B. When specified on contract documents, stainless steel type 304 or type 316 in accordance with ASTM A-240 shall be provided.

III. CONSTRUCTION

A. Unless otherwise noted, all duct and fittings shall be constructed per SMACNA's Duct Construction Standards (+10 in W.G.) shown in the following table:

Diameter (inches)	Galvanized Spiral Duct	Galvanized Fittings
3-10	28	26
12-14	26	24
16-26	24	22
28-36	22	20
38-50	20	20
52-60	18	18

B. FITTINGS:

1. All fitting ends shall come factory equipped with a double lipped, U-profile, EPDM rubber gasket. Gasket shall be manufactured to gauge and flexibility so as to insure that system will meet all of the performance criteria set forth in the manufacturer's literature. Gasket shall be classified by an internationally recognized laboratory authority to conform to ASTM E84-91a and NFPA 90A flame spread and smoke developed ratings of 25/50.

2. All fitting ends shall be calibrated to manufacturer's published dimensional tolerance standard and associated spiral duct.

3. All fitting ends from 3" to 24" diameter shall have rolled over edges for added strength and rigidity.

4. All elbows from 3" to 12" diameter shall be 2 piece die stamped and continuously stitch welded. All elbows 14" diameter and larger shall be standing seam gorelock construction and internally sealed.

5. The radius of all 90° and 45° elbows shall be 1.5 times the elbow diameter, unless otherwise noted on the contract documents to be 1.0 times the elbow diameter. The radius of all 15°, 30° and 60° elbows shall be 1.0 times the elbow diameter.

6. All fittings that are of either spot-welded or button punched construction shall be internally sealed. When contract documents require divided flow fittings, only full body fittings will be accepted. The use of duct taps is unacceptable except for retrofit installations.

7. All volume dampers shall be SPIROsafe type DRU, DSU or DTU or approved equal. Damper shall be fitting sized to slip into spiral duct. Damper shall have the following features:

a. Locking quadrant with blade position indicator
b. 2" sheet metal insulation stand-off
c. Integral shaft/blade assembly
d. Shaft mounted, load bearing bushings
e. Gasketed shaft penetrations to minimize leakage

C. SPIRAL DUCT:

1. Spiral duct shall be calibrated to manufacturer's published dimensional tolerance standard.

2. All spiral duct 8" in diameter and larger incorporates a double corrugation between spiral seams for added strength and rigidity.

3. Spiral seam slippage shall be prevented by means of a flat seam and a mechanically formed indentation evenly spaced along the spiral seam.

IV. PERFORMANCE

A. Duct system performance shall meet SMACNA's Leakage Class 3 requirements at the system design static pressure as indicated on the contract documents not to exceed -20 in W.G. or +12 in W.G.

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