Replacement Actuator Issues for Fire and Smoke Dampers April 2008 1 Fire & Smoke Replacement Actuators 1. Technical Issues 2. Standards and Codes.

Replacement Actuator Issues for Fire and Smoke Dampers April 2008 1

Fire & Smoke ReplacementActuators

1. Technical Issues

2. Standards and Codes


Fire & Smoke Actuator Replacement Starts with the Damper

Five methods were used in past


1.

Single spring for actuator and fusible link.

A thermal disc sensor must be retrofitted.


SPRING NEEDS TO BE DISCONNECTED


The knee-lock is loosened to disconnect the fusible link and spring. Thermal disc is installed with a Belimo.


If a fusible link is on the damper,insert a carriage bolt into the spring arm.Do not remove the other bolt.


An HS10 high limit sensor must be installed.



2. Dual springs – one for fusible link fire function and one for actuator smoke function. This was very common.


Remove the linkage, motor, springs, and mount Belimo. Depending on damper, mounting may require a plate.


Remove the linkage, motor, springs, and mount Belimo. Depending on damper, mounting may require a plate.


3. Single spring with a, thermal disc sensor.

No fusible link. The actuator springs closed for smoke and for fire. Ruskin MA220, MA230 motors. Phillips 150.




Remove spring mechanism.

DANGER. Not typically under extreme load, but could release.

Damper now ready to mount new actuator.


Select orientation to avoid running screws into damper frame and allow available flex to reach.

New flex to ½” connector

Anti-rotation strap

Standard clamp has insert for ½”, 5/8” or remove for 1”


T150 Phillips – No Spring in Motor



4. Modern dampers have spring in actuator.

Some older motors also had the spring in the motor – e.g., MA418.

Some older motors had an obvious external spring.




Prefco

McCabe Link®

If a shaft exists, Belimo can be used.


McCabe® Link

Bimetal

Motor ArmEngaged in Link

The motor arm is engaged in the McCabe® Link above.



Chase nipple & Wiring


OEM bracket hung out in air on small damper.

Anti-rotation strap can be attached to bracket, 4 x 4 plate, or sheet metal bracket.


Best to mount the Belimo anti-rotation strap perpendicular to the actuator to allow for movement on non-concentric shaft. This may be why the HW’s fail.


Variety of ways to use the anti-rotation straps.


5. Oldest original dampers used a number of methods.


Prefco’s that cannot use Belimo for replacement due to mounting and applications.

Rebuild damper or replace.


Actuator is no longer made.

Motors, Crank-arm, and negator spring no longer made.


Air Balance has instruction sheet on how to change to modern thermodisc.


Negator spring version of Air Balance


Fusible rod instead of fusible link.

Note negator springs.



The spring was on the damper blades on fire/smoke dampers. A second door spring added to the actuator when it was used on smoke dampers. The springs must be removed before Belimo installed.

MP2781




The linkage is technically inferior the correct practice is:

Replace the damper.


We could go on and on.

Bottom line:

Take a picture if you can. Get not only make and model of the old motor, but also the make and model of the damper.

Replacement starts with the damper, not the motor.



Fire Department needs to be consulted. The actuator is connected to the alarm system.


Considerations


Replacement Rules:

1. Replacement actuator should be UL555S listed with the damper manufacturer.

2. Obey the TTT-VAT rules:

a. Temperature rating of replacement must be equal or better.

b. Torque should be equal or better

c. Time should be same or better.

d. Voltage must be the same

e. Amperage draw should be equal or less than original.

f. TEST the damper, controls, and actuator when finished.


Torque

OB = 6-10 in- # / sq. ft.

PB = 8-14 in- # / sq. ft.

If in doubt use the highest for estimating. Manufacturers vary significantly.


Breaker loading (20A Emergency circuit)

(15A – other loads) / 1 actuator amp draw

= Number of Actuators


Damper blade switches are subject to broken coat hanger connection.

Actuator aux switches are subject to less problems.

The jackshaft linkage is more solid.

Auxiliary SwitchesNew construction and retrofit issue.


Actuator aux switches are technically equal or superior depending on details.



Codes require all the components be checked. Typically, only the alarm functions are verified.


Now damper is ready for testing. Typically:

1. Apply power and let damper drive open. Cut power and ensure spring closes damper completely. Repeat three times to check assembly.

2. Use heat gun to check thermal sensor. Reset manually.

3. Replace fusible link if required.

4. Other tests per damper manufacturer or local codes.


CODES

UL clearly states in their Marking Guide that they do not regulate replacement market.

NFPA 80 & 105 state clearly that defective dampers should be repaired ASAP.

Local Authority Having Jurisdiction (AHJ) sets the requirements. Almost all administrative and life safety codes state all systems must be kept in operating order.

Codes do not cover replacement in detail since they are new construction oriented.


Local codes vary. In general:

• Fire & Smoke Dampers must be repaired.

• Fire Marshal is informed via form if replacement of actuator only.

• If any alarm or smoke control wires are removed and reinstalled, an inspection is required.


Call AHJ and ask if a permit is required if:

a. Replacement is an actuator that is UL555S Listed with the damper manufacturer,

b. No alarm wiring is being touched,

c. Damper will be conformance tested using manufacturer instructions,

d. A notice form for Fire Marshal will be left on premises. Form has testing checklist.

Remember: LAPF

Possibly the worst pneumonic device ever!


MEA 197-07-M


MEA 197-07-M


MEA 197-07-M

City of New York MEA Belimo documents available:

www.belimo.us/sh/firesmoke/imates/1_MEA_Tag_Regulations.pdf

…2_MEA_F&S_Replacement_Data_&_Cross_ Reference.pdf

…3_MEA_Fire_Marshal_Form F&S_Actuators.pdf

Individual damper manufacturer instructions are available also.


Thank you

Americas

Replacement Actuator Issues for Fire and Smoke Dampers April 2008 1 Fire & Smoke Replacement Actuators 1. Technical Issues 2. Standards and Codes.

Documents

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