Greenheck BS476 User Manual

Tunnel Transit Dampers

• Life Safety

• Heavy Duty Tunnel Transit

March

2007

Heavy Duty/Industrial
Tunnel Dampers

Applications

Dampers in subway tunnels and transit systems serve three primary functions, depending on design of the
ventilation system.

Pressure Equalization

Dampers mounted in the side of the tunnel vent pressurized air in front of a train
and reintroduce air as it passes. In single trackways, this air movement can be
substantial.

Portal Intake and Exhaust

Dampers at tunnel ends control air intake and emergency smoke exhaust in
long tunnels without intermediate air supplies.

Emergency Fire/Smoke Control

Dampers are spaced along the tunnel and can be remotely controlled to
(a) pressurize a tunnel section to allow safe egress of train/automobile
passengers to an escape tunnel, while blowing fire and smoke from this area,
and (b) create negative pressure in the area of the fire to vent smoke and gases.

Tunnel Ventilation Dampers

Road and underground metro tunnels are some of the most difficult environments in the world. High humidity,
dust-laden air, and limited access can make the installation and operation of ventilation systems problematic.
However, these issues become insignificant in the event of an emergency — the dampers and fans that make
up the ventilation system simply must operate when lives are on the line. Greenheck’s tunnel specific dampers,
the HTD series, were designed to meet these challenges.

Construction

Greenheck’s HTD series dampers begin with the
same flange mount, channel style frame as the HCD
line of products. Two blade profiles are offered:
the HTD-630 is designed with a fabricated airfoil
blade, and the HTD-640 uses an extruded aluminum
blade. Several materials can be used to meet
the requirements of each environment, including
galvanized steel, 304 or 316 stainless steel, or
aluminum.

Reliability

In compliance with NFPA 130 and 502, HTD models
are tested in Greenheck’s test facility for operation
up to two hours at 482°F (250°C). HTD-630 has been
tested in accordance to British Standard 476 for 2
hours at Warrington Fire. Our engineering staff has
the experience to perform any additional test as
required including the cyclic pressure test, mimicking
the piston effect caused by passing trains.

Maintainability

HTD dampers are designed to keep maintenance
procedures simple and low frequency. The bearings
on a HTD damper is 316 stainless sleeve type,
requiring no lubrication or maintenance throughout
its useful life. Linkages are designed for L/360
deflection, and each axle is bolted to the damper
blade, allowing for easy removal if repair is needed.

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Features and
Accessories

Blades

Airfoil blades are constructed of double skin galvanized or heavy gauge
aluminum. The airfoil blade design has higher strength when compared to a 3V
blade. HTD-630 features a fabricated airfoil blade. HTD-640 features an extruded
airfoil blades.

Blade Seals

Greenheck recommends silicone blades seals for low leakage performance.

Bearings

316 stainless steel sleeve bearings are standard on Greenheck HTD series
dampers. Options include a self-aligning bronze sleeve with galvanized steel
housing or an external re-lubricatable ball bearing.

Fabricated Airfoil

Extruded Airfoil

316 stainless

steel sleeve

Self-aligning

bronze sleeve

Re-lubricatable

ball bearing

Jamb Seals

Type 304 or 316 stainless steel jamb seals are used to prevent air from leaking between
the ends of each blade and frame.

Axle Seals

O-ring seals are available to prevent air or debris leakage through the axle.

Actuators

Greenheck has a variety of actuators available for the HTD series. The common
models are:

RCS Sure series

• 120V or 230V, 50/60 Hz

• Spring Return

• NEMA 4, 4X & 7
RCS MAR series

• 24V, 120V, or 230V, 50/60 Hz

• NEMA 4 , 4X & 7

• Modulating or power open/close
Siemens 331-2856

• Pneumatic

• Two position

• Maximum 25 psi supply
Hytork XL681SRHT

• Pneumatic

• Two position

• Minimum 80 psi supply

RCS MAR 90

RCS Sure 100

Hytork XL681SRHT

O-ring seal

Siemens

331-2856

Proximity Switch

Proximity switch is mounted to the damper axle to indicate blade position on the damper.
O-rings are used to seal the switch compartment for hazard, corrosion, and leakage protection.
This proximity switch is NEMA 4, 4X, & 7 rated and has been tested to a temperature of 250°C
for 2 hours of operation.

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