Section 15810 FIBERGLASS DUCTING AND FANS

Section 15810

FIBERGLASS DUCTING AND FANS

PART 1 - GENERAL

1.1 THE REQUIREMENT

A. The CONTRACTOR shall furnish and install FRP ductwork systems including duct, bends, fittings, dampers, inline silencers, adaptors transitions, closure pieces, supports, expansion joints, inline fans, acoustical blankets with lagging accessories and appurtenances complete and operable, as shown and specified herein, including manual and electric operators, coating and control units in accordance with the requirements of the Contract Documents.

1.2 RELATED WORK SPECIFIED ELSEWHERE

A. The requirements of the following sections and divisions apply to the Work of this section. Other sections and divisions of the Specifications, not referenced below, shall also apply to the extent required for proper performance of this Work.

1. Section 15000, Piping, General

2. Section 15020, Pipe Supports

3. Section 15030, Piping Identification Systems

4. Section 15064, Pipe: Plastic

5. Section 15100, Valves, General

6. Section 15101, Valve Operators

7. Section 09800, Protective Coating

8. Section 11005, Equipment Basic Requirements

9. Section 15885, Odor Control System

10. Section 16010, Electrical General Provisions

11. Section 16220, Electric Motors

1.3 REFERENCE SPECIFICATIONS, CODES, AND STANDARDS

A. All Work specified herein shall conform to or exceed the applicable requirements of the referenced portions of the following publications to the extent that the provisions thereof are not in conflict with other provisions of these Specifications.

B. Comply with the applicable editions of the following codes, regulations and standards.

1. Industry Standards:

AMCA 500 Test Methods for Louvers, Dampers, and Shutters

ASTM C-582 Standard Specification for Contact Molded Reinforced Thermosetting Plastic (RTP) Laminates for Corrosion- Resistant Equipment

ASTM D-638 Test Method for Tensile Properties of Plastics

ASTM D-790 Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials.

ASTM D 2240 Test Method for Rubber Property - Durometer Hardness

ASTM D 2310 Classification for Machine-Made “Fiberglass” (Glass- Fiber-Reinforced Thermosetting Resin) Pipe

ASTM D 2992 Practice for Obtaining Hydrostatic or Pressure Design Basis for "Fiberglass" (Glass-Fiber-Reinforced Thermosetting Resin) Pipe and Fittings

ASTM D 2996 Filament-Wound "Fiberglass" (Glass-Fiber-Reinforced

Thermosetting Resin) Pipe

ASTM D 3299 Standard Specification for Filament-Wound Glass-Fiber- Reinforced Thermoset Resin Corrosion-Resistant Tanks

ASTM D 3567 Practice for Determining Dimensions of “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pipe and Fittings

ASTM D 3982 Standard Specification for Contact Molded “Fiberglass” (Glass Fiber Reinforced Thermosetting Resin) Duct and Hoods

ASTM E 84 Standard Test Method for Surface Burning

Characteristics of Building Materials

AWWA M-45 American Water Works Manual of Water Supply

Practices "Fiberglass Pipe Design"

SMACNA Thermosetting FRP Duct and Construction Manual

2. Other Standards:

OSHA Occupational Safety and Health Act Standards for Safety

CBC California Building Code

NFPA National Fire Protection Association

SMACNA Sheet Metal and Air Conditioning Contractors' National

Association

C. Comply with the applicable reference Specifications as directed in the General

Requirements and Additional General Requirements.

1.4 CONTRACTOR SUBMITTALS

A. Submittals shall be made in accordance with the General Requirements, Additional

General Requirements and as specified herein.

B. Submittals shall be made in accordance with Section 15000, Piping, General.

1. Duct:

a. Name of manufacturer.

b. Type of resin and identification of composite layers. c. Pressure, vacuum, and temperature rating of duct. d. Dimensions of sub-assemblies to be shipped.

e. Certification of compliance with reference standards. f. Stamped structural design calculations.

2. Dampers:

a. Name of manufacturer.

b. Type, model, materials of construction. c. Pressure rating.

d. Overall dimensions, weight including operator.

e. Certified AMCA 500 D and Bubble-Tight zero leakage test results.

3. Inline Silencers:

a. Name of manufacturer.

b. Type, model, materials of construction. c. Minimum octave band insertion values.

4. Expansion Joints:

a. Name of manufacturer.

b. Type, model, materials of construction.

c. Force required for expansion and contraction.

5. Acoustical Blankets:

a. Name of manufacturer.

b. Type, model, materials of construction. c. Sound Transmission Class Rating.

1.5 QUALITY ASSURANCE A. General:

1. Comply with the requirements specified herein and the applicable reference

Specifications of the General Requirements and Additional General Requirements.

2. Factory Testing:

a. Duct shall be inspected at the factory for compliance with the defect criteria listed below.

b. A randomly selected damper from each size classification shall be tested in accordance with AMCA 500 D and Bubble-Tight at AMCA-approved testing laboratory.

c. Results for tests performed on randomly selected sample fiberglass sections of duct to determine tensile and flexural properties per ASTM D 638 and 790 shall be provided for the engineer’s review prior to shipment.

1.6 WARRANTY

A. Guarantees and Warranty shall be furnished in accordance with “Warranty” (CONTRACTOR’s Guarantee) of the General Conditions and Section 15100, Valves, General for all dampers.

PART 2 - PRODUCTS

2.1 GENERAL

A. Service Conditions: Internally, duct systems will be exposed to air saturated with water vapor containing foul odors, primarily hydrogen sulfide, mercaptans, ammonia and other organic and inorganic compounds typically associated with wastewater treatment. Externally, duct systems will be exposed to odorous air inside the building and outside environmental conditions of sunlight, varying temperatures and humidities, and precipitation.

B. Design Requirements:

1. Duct, adapters, transitions, expansion joints:

a. Internal positive pressure, in. wc – 30. b. Internal vacuum in. wc – 10.

c. Temperature, degrees F 0 to 120.

2. Dampers:

a. Differential pressure, in. wc – 30. b. Internal vacuum in. wc – 10.

c. Temperature, 0 to 120 degrees F.

3. Dimensions: The dimensions shown are net inside, the clear space inside the duct.

4. Physical Properties: Laminates shall have the following minimum properties:

Property	Standard	3/16 inch thick	1/4 inch thick
Ultimate Tensile Strength, pounds per inch	ASTM 638	9,000	12,000
Flexural Strength, pounds per inch	ASTM 790	16,000	19,000
Flexural Modulus of Elasticity, pounds per inch (tangent)	ASTM D 790	700,000	800,000

5. Reinforcement: Bends, fittings and special sections shall be reinforced or shall have shell thickness increased at those locations where the combined stresses due to internal pressure and bending will exceed the maximum stress recommended by the manufacturer. The duct manufacturer shall determine and provide reinforcements or additional shell thicknesses as required to keep the combined stresses within the recommended maximum.

6. Structural Criteria:

a. Round duct shall have a safety factor of 10 to 1 for pressure and 5 to 1 for vacuum service. Rectangular sections shall require special design consideration that shall be submitted to the ENGINEER for review and acceptance. Rectangular duct design shall be based on a maximum of 1 percent side wall deflection. Minimum wall thickness for round and rectangular duct shall be 3/16 inch.

b. After installation, horizontal rectangular duct shall not sag more than 2 percent of the shortest side dimension, measured from the theoretical centerline of the duct to the actual centerline at the midpoint between supports. Maximum sag of horizontal round duct shall not exceed 2 percent of diameter.

c. When necessary, sections of ductwork weighing more than 100 pounds shall be lifted using spreader bar and straps rigged to prevent distorting or damaging it.

7. Chemical Resistance: The FRP duct shall provide chemical resistance to acids, caustic, water, hydrogen sulfide and other sulfide and disulfide compounds, mercaptans, and other materials commonly encountered in odorous air streams from wastewater treatment plants.

8. Flame Spread: FRP ducting and fabrications shall not exceed a flame spread index of 25 and smoke development rating of 50 when tested in accordance with ASTM E 84.

9. FRP Defects: FRP ductwork shall satisfy the following criteria:

Defect	Surface Inspected
	Inside Surface	Outside Surface
Blisters	None	Maximum dimension: 1/4-inch diameter x 1/8 inch high; Maximum density: 1/ft2. Minimum separation: 2 inches apart
Chips	None	Maximum dimension of break: 1/4- inch and thickness no greater than 10 percent of wall thickness; Maximum density: 1/ft2.
Cracks	None	None
Crazing	None	Maximum dimension: 1/2 inch. Maximum density: 5/ft2. A Minimum separation: 2 inches
Exposed Glass	None	None
Scratches	None	Maximum length: 1 inch; Maximum depth: 0.010 inch
Burned Areas	None	None
Surface Porosity	None	None
Foreign Matter	None	None
Sharp Discontinuity	None	None
Pits	Maximum dimensions: 1/8 inch by 1/32 inch deep; Maximum number: 10/ft2.	Maximum dimensions, 1/8” dia. x 1/16 inch deep. Maximum number, 10/ft2.
Dry Spot	None	1 in2 per ft2
Entrapped Air	None at the surface; 1/16 inch and 10/in2 maximum density within laminate	1/8 inch and 4/in2 or 1/16 inch and 10/in2
Wrinkles & Solid Blisters	Maximum deviation, 20 percent of wall thickness, but not exceeding 1/8 inch.	Maximum deviation, 20 percent of wall thickness, but not exceeding 3/16 inch.

C. Ductwork and fittings shall have the manufacturer's name printed on the exterior surface.

2.2 DUCTWORK SYSTEMS

A. Round Duct: Filament wound, complying with ASTM D2996.

B. Fittings and Flanges: Manufacturer's standard, shop-fabricated, compatible with duct, chemically resistant same as duct, complying with ASTM D2996. Flanges shall be at least 3/4 inch thick.

C. Manufacturers: Duct, flanges, and fittings acceptable manufactured, Or Equal:

1. Belco Manufacturing Company

2. Viron International Corporation.

3. Daniel Mechanical Company.

D. Flange Gaskets: Full face, Hypalon, 3/16 inch min. thickness, hardness of

Durometer 50 to 70 when tested according to ASTM D 2240.

E. Bolts, Studs, Washers, Nuts: 316 stainless steel.

F. Drains and Valves: All horizontal duct sections shall be provided with gentle slope to facilitate drainage of any accumulated liquid inside. At the lowest point and as indicated on Drawings CONTRACTOR shall install drain valves of the sizes indicated on drawing. Valves shall be ball type with PVC material for indoor installations and CPVC material for outdoor installations in reference to Section 15064, Pipe: Plastic.

G. FRP Construction:

1. Resin: Resin shall be premium corrosion-resistant, fire resistant vinyl resin as recommended by the manufacturer for the intended service. Resin shall be Hetron

992 FR by Ashland Chemical or the equivalent of either Derakane by Dow Chemical or CoREZYN by Interplastic, Or Equal.

2. Fiber Glass Reinforcement: Chopped strand fiber glass mat shall be used as reinforcement material. Alternatives such as synthetic fiber cloth, woven roving, fiber glass cloth, chopped strand fiber glass spray-up, or filament may be accepted, subject to review by the ENGINEER.

3. Laminates:

a. Inner Surface: The inner surface exposed to the exhaust/foul air environment shall be a resin-rich liner between 0.01 inch and 0.02 inch thick obtained by using one layer of Nexus veil saturated with resin.

b. Interior Layer: The interior layer shall consist of chopped strand glass mat or chopped glass roving saturated with resin to achieve a minimum thickness of

0.10 inch (100 mils).

c. Structural Layer: The structural layer shall be fabricated using either hand layup construction per ASTM D2996 or filament wound, depending on the duct shape in cross-section.

d. Outside Coat: The outside coat shall be resin rich with no exposed raw fibers. For interior duct, the final coat shall be an acceptable factory applied intumescent coating to achieve the designated results for low smoke development. For exterior duct, the final coat shall be an acceptable resin coat with ultraviolet (UV) inhibitor or a suitable paint resistant to UV attack on the surface. The color shall be per Section 15030, Piping Identification Systems.

4. Expansion Joints: Expansion joints shall be of a material resistant to UV light and shall be fabric-reinforced Hypalon.

a. Expansion joints shall be slip-on or flanged type. The slip-on type shall be sized to fit tightly on the outside diameter of the duct and shall be secured in place by stainless steel worm screw type adjustable clamps to provide a gas-tight connection. Flange type expansion joints shall have split stainless steel retaining rings and shall have dimensions and bolt hole drilling patterns and bolt hole diameters to match mating flanges of duct or equipment.

b. Expansion joints shall be capable of compressing and elongating 1-inch under a maximum force of 100 pounds or less. The joints shall also allow lateral deflections of up to 1 inch. Expansion joint material shall be stiff enough to prevent sagging or contraction due to internal vacuum.

2.3 DAMPERS

A. Components:

1. Frame: Fiberglass reinforced plastic with vinyl ester resin (and UV inhibitors where dampers are located outside).

2. Blade: Fiberglass reinforced plastic; stiffeners as required. If the largest dimension is 30 inches and less, thickness shall be at least 0.375 inch. If larger than

30 inches, 0.50 inches thick.

3. Axle: Continuous solid 316 stainless steel rod.

4. Bearings: Molded PTFE.

5. Blade Stops: Fiberglass reinforced plastic bar.

6. Blade Seals: Annular corrosion resistant elastomer. Hypalon shall be acceptable.

7. Shaft Seal: Neoprene.

8. Flanges: Flanges shall comply with ASTM D2996 at a design pressure of 25 pounds per inch and shall have ANSI B16.1 Class 25 diameter and drilling.

a. Gasket: EPDM.

B. Construction: Dampers shall be of the single-blade type complete with single-molded FRP housing and close-fitting blade, full-length axle, and bearings. The damper shall be constructed of fiberglass reinforced plastic using a vinyl ester resin similar to the duct and shall have the same dimensions as the inside of the connecting ductwork. Axles shall be not be less than 1-inch in diameter for damper sizes greater than 12” and shall be continuous through the damper.

1. Dampers shall have a minimum pressure rating of 30-inches of water column. Dampers used for isolation service shall be furnished with a blade seal and shaft seal. Dampers used for balancing shall be furnished with a full circumference molded in blade stop. Isolation dampers shall be “Bubble-Tight” zero leakage type. Certified AMCA 500D bubble tight leakage tests shall be furnished as part of the submittal. Bubble-tight test shall be conducted with non-detectable zero leakage rate at 30” of w.c. pressure and vacuum. Dampers shall be AMCA rated and licensed to bear the AMCA seal. Listing of names of manufacturers in the specifications does not relieve the manufacturer of demonstrating to the satisfaction of the reviewing engineer that the above requirements are fully met without exceptions.

2. Round dampers manufacturer and model, Or Equal:

a. Swartwout Model SBTR92.

b. Belco Manufacturing Company, Model 204.

c. Daniel Mechanical Company, DanELAST Model 303.

3. Backdraft dampers manufacturer and model:

a. Swartwout Model 861. b. Belco Backdraft.

c. Or Equal.

C. Hand Actuators: Dampers shall be provided with hand operators.

1. Hand actuators for dampers 24 inches in diameter and larger shall be worm geared driven, totally enclosed, weather-proof, and permanently lubricated in a die- cast aluminum housing. Housing shall be epoxy coated in the factory with a minimum dry film thickness of 8 mils. Worms shall be heat-treated carbon steel and worm wheels shall be ductile iron. Shafting shall be 316 stainless steel. Shaft and worm wheel seals shall be Buna-N rubber. Actuator shall be bolted to the duct with 316 stainless steel bolts. Hand wheel sizes shall be computed assuming a maximum rim effort of 40 pounds. The allowable number of turns of the hand wheel in order to rotate the blade 90 degrees shall be a minimum of 4 and maximum of 12. Actuators shall be provided with indicating arrows to clearly identify directions of rotation for opening and closing of the dampers. Arrows shall be clearly legible and of substantial durability.

2. Hand actuators for dampers less than 24-inch diameter shall be heavy duty, lever type actuators. Each heavy duty hand actuator shall be constructed of Type 316 stainless steel and shall have a locking quadrant suitable for positioning the blade at any intermediate position.

3. All dampers with shaft centerlines more than 5 feet 6 inches above the floor shall be provided with chain wheels and operating chains. Each chainwheel shall be equipped with a chain guide that will permit rapid handling of the operating chain without "gagging" of the wheel and will also permit reasonable side pull on the chain. Suitable actuator extensions shall be provided, if necessary, to prevent interference of chain and adjacent piping or equipment below. Operating chains shall be hot-dip galvanized carbon steel and shall be looped to extend within 4 feet of the floor below damper.

4. Galvanized tie-back hooks shall be provided on adjacent pipe supports to hold operating chains out of walkways or maintenance access areas when the damper is not being operated.

2.4 IN-LINE FIBERGLASS REINFORCED PLASTIC FANS:

A. General: Provide fiberglass reinforced plastic (FRP) axial fans of sizes, arrangements, accessories and capacities as indicated or as specified herein.

1. AMCA A or B rated. B. Fan Units:

1. Provide factory assembled and tested fan units consisting of a housing, a wheel, a fan shaft, bearings and a support structure.

C. Housing:

1. Provide housings constructed of solid FRP.

2. Inlet and drive side stands constructed of steel with interior surface shielded with

FRP.

3. Exterior metal surfaces to be cleaned and coated with high solids vinyl coating 4 to 5 mils thickness.

4. Inlet and drive side plates to be fastened to housing with imbedded, FRP

encapsulated Type 316 stainless steel bolts.

5. The outlet flange and inlet collar are constructed of solid FRP.

D. Wheels:

1. Provide blades constructed of solid FRP.

2. Key wheels to shafts.

3. Statically and dynamically balance wheels after assembly.

4. Abrasion resistant ceramic coating, 50-60 mils. E. Shafts:

1. Construct shafts of AISI 1040 or 1045.

2. Solid hot-rolled steel, turned, polished and encapsulated in FRP through the shaft seal.

3. Provide FRP stuffing box and gasketed housing shaft seal. F. Bearings:

1. Heavy-duty.

2. Grease lubricated.

3. Precision.

4. Anti-friction ball or roller.

5. Self-aligning.

6. Pillow block-type bearings.

7. Minimum average L-50 life of 200,000 hours. G. Drive:

1. Provide a V-belt drive with belt guard.

2. Selected for a 1.4 service factor.

3. Provide removable full-size Lexan (clear) plastic plates in belt guard housing for visual inspection of fan belt and motor rotation.

4. Provide 1 inch wide orange paint marking on belts for visual confirmation of fan belt rotation.

5. Provide explosion-proof motors. H. Vibration Control:

1. Provide vibration control, in accordance with paragraph 2.1. I. Accessories: Provide the following accessories.

1. Access doors: Neoprene gasketed FRP access door in the housing.

2. Drain connections:

a. Provide 2 inch threaded coupling drain connections the lowest point of the housing.

3. Disconnect switch.

J. Size and capacity as per schedule or as indicated on Drawings. K. Acceptable manufacturer, Or Equal:

1. Hartzell.

2. Universal.

3. Aerovent.

L. Inline Fan Schedule:

Tag ID	15KFAN100	15KFAN105	15JFAN954
Capacity, cfm	15,000	3,000	10,700
Pressure (IN W.C.)	4.3	1.5	3.0
Diameter, inch	36	16	36
Construction	FRP	FRP	FRP
Maximum HP	25	5	15
Maximum RPM	1,800	1,800	1,800
Motor	TEFC	TEFC	TEFC

2.5 INLINE SILENCERS A. Inlet Silencer

1. Inline silencers shall be provided on the inlet sides of the three odor control scrubber fans that provide the following minimum octave band insertion loss values:

63 Hz	125 Hz	250 Hz	500 Hz	1 kHz	2 kHz	4 kHz	8 kHz
16 dB	20 dB	15 dB	24 dB	33 dB	44 dB	48 dB	53 dB

2. The silencers shall be Model 3636 FGR-IL high efficiency manufactured by Innovative Metal Industries or similar performance manufactured by UNCER Technologies Or Equal.

3. Attenuation material shall be fiberglass acoustical insulation bounded to 26 gauge acoustical barrier. All exposed faces shall be bonded with a fiberglass scrim cloth to a minimum strength of 80 lb per square inch.

4. Fiberglass shall be vermin and moisture proof with flame-spread maximum of 25.

5. Outer casing shall be fully welded 316 stainless steel.

6. Spiral rods shall be 316 stainless steel.

7. Unit shall be tubular design with inner diameter of 36-inch.

8. Flanges shall confirm to ANSI B16.1 Class 25 diameter and drilling.

9. Maximum pressure drop shall be 0.50 in-wc at maximum flow of 20,000 cfm. B. Outlet Silencer

1. Inline silencers shall be provided on the outlet sides of the three odor control scrubber fans that provide the following minimum octave band insertion loss values:

63 Hz	125 Hz	250 Hz	500 Hz	1 kHz	2 kHz	4 kHz	8 kHz
14 dB	23 dB	27 dB	35 dB	45 dB	55 dB	42 dB	41 dB

2. The silencers shall be Model MVA-2224-2 high efficiency manufactured by Innovative Metal Industries or similar performance manufactured by UNCER Technologies Or Equal.

3. Attenuation material shall be fiberglass acoustical insulation bounded to 26 gauge acoustical barrier. All exposed faces shall be bonded with a fiberglass scrim cloth to a minimum strength of 80 lb per square inch.

4. Fiberglass shall be vermin and moisture proof with flame-spread maximum of 25.

5. Outer casing shall be fully welded 316 stainless steel.

6. Spiral rods shall be 316 stainless steel.

7. Silencer shall be rectangular with maximum dimensions of 24-inch width x 48- inch height x 30-inch length.

8. Flanges shall confirm to ANSI B16.1 Class 25 diameter and drilling.

9. Maximum pressure drop shall be 0.64 in-wc at maximum flow of 20,000 cfm.

2.6 ACOUSTICAL BLANKETS

A. Acoustical blankets shall be use in lagging the following items in the odor control system and duct work:

1. Fans for the three odor control scrubber.

2. Scrubbers fan inlet and outlet inline silencers.

3. All the duct work from the south wall of the centrifuge building to the inlet side of the odor control scrubbers.

B. The lagging shall consist of acoustical blankets that provide a minimum sound transmission class (STC) rating of 32 and provide the following minimum octave band sound transmission loss values:

125 Hz	250 Hz	500 Hz	1 kHz	2 kHz	4 kHz
13 dB	20 dB	29 dB	40 dB	50 dB	55 dB

C. The acoustical blankets shall be 2 inches thick Model BBC manufactured by Sound

Seal or similar specifications manufactured by Acoustical SOLUTIONS Or Equal.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Field Measurements: Duct lengths shall be determined from measurements taken at the Site. Dimensions shown on Drawings are approximate, not for fabrication.

B. Delivery, Storage, and Handling: Duct, fittings, and dampers shall be protected from damage and shall be properly supported to avoid damage due to flex strains during shipping and installation. Debris or other extraneous material shall not be allowed to enter the duct. Duct, fittings, and dampers shall not be thrown or dropped.

C. Installation: Ducts shall be installed as indicated. All necessary provisions shall be taken into consideration during fabrication and installation of ductwork to provide for expansion and contractions. Ductwork shall be free from vibration when in operation. All necessary vibration isolation devices shall be provided.

1. Anti-seize compound shall be applied to bolt threads.

2. Smooth bends or internal turning vanes shall be installed at elbows, tees, and other points where air flow changes direction.

3. The ductwork shall be supported per manufacturer's recommendation and as required herein.

4. The inside of duct, specials, and fittings shall be smooth, clean, and free from blisters, sand, and dirt when installed.

5. Ductwork shall be airtight.

D. Joints: Joints shall be carefully and neatly made in accordance with the requirements herein and as recommended by the manufacturer.

E. Flanges: Flange bolts shall be tightened sufficiently to slightly compress the gasket and make a good seal, but not so tightly as to distort the flanges. A flat washer shall be installed under each nut and bolt head.

F. Dampers shall be positioned to fit in the connecting ductwork at the locations indicated on the Drawings. Unless necessary for proper operation of the damper, axles shall be installed in the horizontal position.

G. Supports and Hangers:

1. Supports for the FRP duct shall comply with SMACNA Standards and appropriate code requirements for aluminum duct installation. Supports and hangers shall transmit all loads into the building structural frame through a system of intermediate beams and struts as necessary to comply with these Specifications. The CONTRACTOR shall submit his proposed support details plan to the ENGINEER for acceptance.

2. Supports or hangers employing clip angles or similar devices for attachment to the duct are prohibited and all supports shall be designed to resist IBC Zone 4 seismic forces. Supports shall be as indicated in Section 15020, Pipe Supports.

H. Alignment and Elevation: Ductwork shall be provided to the lines and elevations indicated and shall slope to facilitate water drainage where indicated. Laser beam equipment or surveying instruments shall be used to maintain alignment and elevation. If laser beam equipment is used, periodic elevation measurements shall be made with surveying instruments to verify accuracy. If such measurements indicate thermal deflection of the laser beam due to differences between the ground temperature and the air temperature within the duct, precautions shall be taken to prevent or minimize further thermal deflections.

3.2 DUCT CLEANING

A. Duct shall be blown clean of dust and debris using compressed air. The system fans shall not be used to provide air for duct cleaning. The duct being cleaned shall be purged continuously for not less than 48 hours at a flow rate not less than the design flow rate for that duct section.

3.3 TESTING

A. Field Testing: Foul air ducts shall be field tested to condition specified in the pipe schedule with zero leakage. Leaking components shall be replaced or repaired and test shall be repeated to the satisfaction of the Engineer. Field certification of zero leakage shall be submitted after the test with all action taken during the test such as repairs and replacement of components are indicated.