Extractor Ventilation Exhaust Fan Installation Method Statement

This method statement covers the procedure or sequence of installation of Ventilation & Exhaust Fans in different areas and for different types of fans. The procedure is applicable for any kind of HVAC project.

Overall project manager and project mechanical engineer are responsible for the implementation of this procedure.

The exhaust fans installation shall be in compliance with project specifications, manufacturer instructions and applicable local and international standards.

During and before the ventilation fans installation works all site safety rules & regulations shall be complied.

Supervisors will deliver tool box talks, relevant to these activities to all operatives involved in the installation and proper records shall be maintained.

All operatives will be equipped with minimum personnel protective equipment; hard hat, coveralls, safety boots, safety glasses.

The persons using cleaning fluid, solvent cement & any other forms of chemicals have to wear hand gloves and safety goggles.

Only qualified personnel shall be allowed to perform the exhaust fans installation works.

During installation, display warning sign boards to be provided and barricade the area whenever necessary.

Close monitoring by the site engineers during installation is highly recommended.

Only competent, experienced & trained personnel shall perform all the required activities stated in this method statement.

Ensure that all operatives fully understand the method of installations.

Typical Installation Procedures for Ventilation & Exhaust Fans

Make sure that reinforced poured concrete pad with structural steel base or inertia base is available for the installation of fans.

To eliminate vibration and noise from being transferred to the building, vibration isolators shall be installed.

The fan is mounted directly on the isolation base and must be supported for the entire length of the fan base angle.

Ensure that the isolators are installed between the isolation base and the foundation.

After the fan, isolation base, and isolators are installed, the entire assembly must be levelled.

Position the level on the isolation base, not the fan shaft, for proper levelling.

Ensure that the motor and fan shafts must be level and parallel relative to each other for proper alignment.

Rotatable Housings

It may be necessary to rotate the scroll of the fan to achieve different discharge position than what was originally supplied.

This is accomplished by removing the housing bolts, rotating the housing to a new discharge position and reinstalling the bolts.

Radial Gap, Overlap & Wheel Alignment

Efficient fan performance can be maintained by having correct radial gap, overlap and wheel alignment.

These item should be checked after the fan has been in operation for 24 hours and before start-up after the unit has been serviced.

Radial gap is adjusted by loosening the inlet cone/ ring bolts and centering the cone/ring on the wheel.

If additional adjustment is required to maintain constant radial gap, loosening the bearing bolts and centering the wheel is acceptable as a secondary option.

Overlap is adjusted by loosening the wheel hub from the shaft and moving the wheel to the desired position along the shaft.

There should be a smooth feel to the profile when moving from one component to the other.

Overlap on double width fans is set by having equal spacing on each side of the wheel.

Wheel Alignment: Correct wheel alignment for an industrial process by centering the wheel in the housing.

V-Belt Drives

Remove the protective coating from the end of the fan shaft and assure that it is free of nicks and burrs.

Check fan and motor shafts for parallel and angular alignment.

Slide sheaves on shafts – do not drive sheaves on as this may result in bearing damage.

Align fan and motor sheaves with straight edge or string, and tighten.

Place belts over sheaves.

Do not pry or force belts, as this could result in damage to the cords in the belts.

Adjust the tension until the belts appear snug.

Run the unit for a few minutes and allow the belts to seat properly.

With the fan off, adjust the belt tension by moving the motor base.

When in operation, the tight side of the belts should be in a straight line from sheave to sheave with a slight bow on the slack side.

 Ducted Outlet Installations

Discharge Duct Turns: Duct turns located near the fan discharge should always be in the direction of the fan rotation.

Fan performance is reduced when duct turns are made immediately off the fan discharge.

To achieve catalogued fan performance there should be at least three equivalent duct diameters of straight ductwork between the fan discharge and any duct turns.

Ducted Inlet Installations

Inlet Duct Turns: Installation of a duct turn or elbow too close to the fan inlet reduces fan performance because air is loaded unevenly into the fan wheel.

To achieve full fan performance, there should be at least one fan wheel diameter between the turn or elbow and the fan inlet.

Inlet Spins: Inlet spin is a frequent cause of reduced fan performance.

The change in fan performance is a function of the intensity of spin and not easily defined.

Ensure that proper duct design and air flow patterns are achieved.

Non-Ducted Inlet Clearance

Installation of a fan with an open inlet too close to a wall or bulkhead will cause reduced fan performance.

It is desirable to have one fan wheel diameter between parallel fan units and minimum of three-fourths of a wheel diameter between the fan inlet and the wall.

Plenum and Plug Fans Installations

Adjacent Walls: The distance between fan and walls or ceilings will effect the performance of the fan.

The recommended distance between the fan wheel and any wall is a minimum of one-half wheel diameter.

Multiple walls reduce the performance even more.

Side by Side: When two or more plenum fans are in parallel, there should be at least one fan diameter spacing between the wheels.

Applications with less spacing will experience performance losses.

Outdoor Installation

Fans are listed for a maximum operating temperature of 375°F and include a bolted access door and 1 inch drain connection.

An outlet guard is strongly recommended when the fan discharge is accessible.

The fan discharge must be a minimum of 40 inches above the roof line and the exhaust duct must be fully welded to a distance of 18 inches above the roof surface.

 Installation Procedure for each Fan Names & Area of Use

Centrifugal Exhaust Roof Exhaust Fan for Battery Room

Fans are to rigged and moved by lifting brackets provided or by the skid when a fork lifts are used.

Location of brackets varies by fan model & sizes.Extractor Ventilation Exhaust Fan Installation Method Statement

Check the location of brackets from the unit for lifting.

Fan shall not be lifted by the shaft, housing, motor, belt guard or accessories.

Handle in such a manner as to keep from scratching or chipping the coating.

Damaged finish may reduce ability of fan to resist corrosion.

When installing the fans, ensure the proper protective devices are used to protect personnel from moving parts and other hazards.

Electrical Disconnects:

Fan motors should have disconnects located in close visual proximity to turn off electrical service.

Service disconnects shall be locked out when maintenance is being performed.

Moving Parts:

All moving parts must have guards to protect personnel.

Fully secure fan wheel before performing any installation or maintenance.

Check guards (Belt, shaft, inlet, and outlet) that they are secure & installed properly.

Note that the fans are listed for a maximum of 375°F and include a bolted access door and 1 inch drain connection.

An outlet guard is strongly recommended when the fan discharge is accessible.

An up blast discharge is recommended.

The fan discharge must be a minimum of 40 inches above the roof line and the exhaust duct must be fully welded to distance of 18 inches above the roof surface.

 Emergency Spill Exhaust Fans for Chemical Store, Fresh Chemical & Solvent Store, Chemical Supply & Kitchen Hoods

Upon receiving unit, check for any damage and or missing accessories & report/ return to shipper/ supplier.

When lifting the unit, use either the (4) lifting points on the drive frame or (2) lifting points on the bearing plate if present.

Move the fans to the desired location using lifting points and fasten securely through the mounting holes in base.

Shims may be necessary depending upon roofing material thickness.

The motor amperage and voltage rating must be checked for compatibility to the supply voltage prior to final electrical connection.

For non-flammable applications the electrical supply can be routed through the conduit chase between the curb cap and the bottom of the motor compartment.

A drain trough is provided on all fans for single point drainage of water and other residue.

Drain point shall be connected to the nearest drainage system.

Check all fasteners for tightness.

The wheel should rotate freely and be aligned.

Wheel position is preset and the unit is test run at the factory.

Movement may occur during shipment, and realignment may be necessary.

Centering can be accomplished by loosening the bolts holding the drive frame to the shock mounts and repositioning the drive frame.

Wheel and inlet cone overlap can be adjusted by loosening the set screws in the wheel and moving the wheel to the desired position.

Direction of rotation is critical.

Reversed rotation will result in poor air performance, motor overloading and possible burnout.

Check wheel rotation by momentarily energizing the unit.

Rotation should be clockwise and correspond to the rotation decal on the unit.

If adjustments are made, it is very important to check the pulleys for proper alignment.

Misaligned pulleys lead to excessive belt wear, vibration, noise and power loss.

Assembly of Hooded Propeller Fans:

Unpack & inspect all the parts.

Each fan that is shipped knocked down has the following hardware package containing:

Hood Support Fasteners,

Hood Fasteners &

Birdscreen/ Filter Fasteners.

Installation of Hood Support Rails:

Fasten hood support rails with 3/8”-16 x ¾” hex head spinlock bolts & nuts.

The bolts that fasten the fan panel to the base will also be used to secure the hood support rails and filter retaining angles.

Remove the 3/8”- 16 x ¾” bolts from one side of the fan panel.

Assemble the parts and wrench tightens the hood support rails and filter retaining angles perpendicular to fan drive frame.

Mounting holes in fan base will line up with holes in hood support rails and filter retaining angles.

Installation of Filter Channel:

Install filter channels with 5/16”-18 x ¾” weld studs and spinlock nuts.

Finger tightens the channels in place.

Bolt hole locations are typical but larger units will have additional filter end channel sections.

Install Filter End Angles with 5/16” – 18 x ¾” weld studs and spinlock nuts.

Finger tighten the end angles in place.

Note correct position of end angle with angle leg down and facing the fan base.

After all filter channels and end angles are bolted together, square-up assembly and wrench tighten all fasteners.

Install the filters.

Slide filters into filter channels, no fasteners or hardware are required.

Install the Hood Rails with 3/8”- 16 x 1 ½” hex head spinlock bolts and nuts.

Position the hood rails and finger tighten the fasteners.

These fasteners will be wrench tightened after the hood panels are installed and secured.

Install the Hood Panels with 3/8” sheet metal screws with washer.

Locate the male hood enclosure panel.

Start with this assembly first.

This is the starter panel.

Place this panel on the hood rails and fasten tight with four screws.

Install the intermediate panels one at a time.

The panels have interlocking ribs.

For fan sizes 48 & larger, hood clips must also be installed on each panel.

Each panel is predrilled for hood clip installation.

Secure each hood clip with a screw and secure each intermediate panel to the hood rails with four screws.

Install the female hood enclosure panel.

Secure this panel to the hood rails with four screws.

Reinstall the hood clips, remove the end filters prior to installing and securing the female hood enclosure panel to gain access to the underside of the hood.

Reinstall the end filters after hood clips are installed.

Toilet Exhaust Fans Installation

Toilets exhaust fans are thoroughly inspected and test run at the factory.

Items such as proper wheel alignment, balance, vibration and workmanship are analyzed by quality control personnel using state-of-the-art equipment.

Prior to installation, the unit must be carefully inspected for visible damage or concealed damage during handling and shipping.

Fans are to be rigged by either the lifting brackets provided or by the skid when a forklift is used.

All toilet fans inline model have mounting brackets located at the ends of fan housing with which slings can be attached.

Fans should not be lifted by the shaft, housing, motor, belt guard or any accessories.

Any installation with inlet or discharge configurations that deviate from manufacturer’s recommendation may result in reduced fan performance.

Restricted or unstable flow at the fan inlet can cause pre-rotation of incoming air or uneven loading of the fan wheel yielding large system losses and increased sound levels.

Free discharge or turbulent flow in the discharge ductwork will also result in system effect losses.

Typical installations for Toilet Exhaust fans are horizontal & vertical mounting with motor in the 3 or 9 o clock position or vertical installations.

Additional mounting rails are recommended.

Electrical Connections:

Before electrical connections are made, the supply voltage, phase and ampere capacity must be checked for compatibility with the fan motor.

In addition, the supply wiring must be properly fused and conform to local & national electrical codes.

Exhaust Fans for Staircase, Generator Room & Lifts

Inspect the unit for any damage and report supplier/ manufacturer immediately.

Check all accessories are counted for.

Move the fan to the desired location and fasten securely through mounting holes provided in the base angles.

The unit must be level (shimming may be necessary).

Flexible duct connections and vibration isolators should be used where noise is a factor.

The motor voltage and ampere rating must be checked for compatibility with the electrical supply prior to final electrical connection.

Supply wiring to the fan must be properly fused and conform to local and national electrical codes.

The discharge is factory set, however, it can be rotated to other discharge positions in the field if necessary.

Removal of the housing bolts allows the discharge to be rotated to the clockwise position.

Fan rotation is always viewed from the drive side of the housing.

Wheels must rotate freely and not rub on the inlet venture.

Rotation direction of the wheel is critical and incorrect rotation will result in reduced air performance, increased motor loading and possible motor burnout.

Check wheel rotation by momentarily energizing the unit and noting if rotation is in the same direction as the airflow at the outlet and conforms to the rotation decal affixed to the unit.

Exhaust Fans Installation for Pump Rooms

Upon receiving the unit, check for any damage and report immediately to the supplier/ manufacturer, also check that all accessories are available.

When lifting unit on to roof, use either the 4 lifting points on the drive frame or the 2 lifting points on the bearing plate if present.

Access to the drive frame is accomplished by removing the screws.

The cover can then be removed and placed on a flat surface in an area protected from strong winds.

Move fan to desired location using lifting points and fasten securely through mounting holes in base, shims may be used depending upon roofing material thickness.

Check all fasteners for tightness.

The wheel should rotate freely and be aligned.

Wheel position is preset and the unit is test run at the factory.

Movement may occur during shipment, and realignment may be necessary.

Centering can be accomplished by loosening the bolts holding the drive frame to the shock mounts and repositioning the drive frame.

Wheel and inlet cone overlap can be adjusted by loosening the set screws in the wheel and moving the wheel to the desired position.

Direction of wheel rotation is critical, reversed rotation will result in poor performance, motor overloading and possible burnout.

Check wheel rotation (viewing from shaft side) by momentarily energizing the unit, rotation should be clockwise and correspond to the rotation decal on the unit.

If adjustments are made, it is very important to check the pulleys for proper alignment, because misaligned pulleys lead to excessive belt wear, vibration, noise and power loss.

Belt tension can be adjusted by loosening four fasteners on the drive frame.

The motor plate slides on the slotted adjusting arms & drive frame angles in the same manner.

Belt tension should be adjusted to allow 1/64 inch of deflection per inch of belt span.

The adjustable motor pulley is factory set for the RPM.

Speed can be increased by closing or decreased by opening the adjustable motor sheave.

The motor’s amperage and voltage ratings must be checked for compatibility to supply voltage prior to final electrical connection.

Exhaust Fans for Laboratory & Office Area

It is important that the unit must be inspected for visible & concealed damage before beginning installation of fans.

Check and make sure that all accessory items have been received and available at the time of exhaust fan installation.

Units are being lifted using minimum of four points on the fan housing or attach two suitable chains/ straps around the entire body.

Any installation with inlet or discharge configurations that deviate manufacturer recommendations may result in reduced fan performance.

Restricted or unstable flow at the fan inlet can cause pre-rotation of incoming air or uneven loading of the fan propeller yielding large system losses and increase in sound levels.

Free discharge or turbulent flow in the discharge ductwork will also impact the system performance.

Before electrical connections are made, the supply voltage and ampere must be checked for compatibility with the fan motor.

The supply wiring must be properly fused and conform to local and national electrical codes.

Power supply wires are then connected to an optional safety disconnect switch, to the optional wiring pigtail or directly to the motor junction box.

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