All Actuators Types (Pneumatic, Electrical) Technical Requirements in IAS

This article is about general and technical requirements for All Actuators Types (Pneumatic, Electrical) used in Integrated Automation System or Building Automation System.

All Actuators Types (Pneumatic, Electrical) Technical Requirements in IAS

• Actuators <Modify as required to match project design, delete sections that are not relevant>
  1. General: Size actuators and linkages to operate their appropriate dampers or valves with sufficient reserve torque or force to provide smooth modulating action or 2-position action as specified. Select spring-return actuators with manual override to provide positive shut-off of devices as they are applied. Manual override shall allow the user to disengage the valve/damper from the actuators motor for manual operation. Large valve actuators shall provide fly wheel for manual operation.

  2. Actuators General Requirements:

     • Ambient Operating Temperature Limits: -10 to 150 degrees F (-12.2 to 66 degrees C).
     • Two Position Electric Actuators: Line voltage (120 volt, 24 volt) with spring return.  Provide end switches as required.
     • <Pneumatic Actuators: Provide heavy-duty actuators with stroke indication and spring return.  Actuator shall consist of steel or aluminum cylinder and pistons.  Housing shall be protected both internally and externally with corrosion resistant coating.  Provide position feedback positive positioners with adjustable start point and operating range.  Positive positioners shall be provided on all pneumatic valves larger than 1 inch.>
     • Electronic Actuators: Provide actuators with spring return for two-position (24v), 0-5 VDC, 0-10 VDC, 2-10VDC, 4-20 mA, as required.  Actuators shall travel full stroke in less than 90 seconds.  Actuators shall be designed for a minimum of 60,000 full cycles at full torque and be UL 873 listed.  Provide stroke indicator.  Actuators shall have positive positioning circuit. Where two actuators are required in parallel or in sequence provide an auxiliary actuator driver. Actuators shall have current limiting motor protection.  Actuators shall have manual override where indicated.  Modulating actuators for valves shall have minimum range of 40 to 1.
     • Close-Off Pressure: Provide the minimum torque required, and spring return for failsafe positioning (unless otherwise specifically indicated) sized for required close-off pressure. Required close-off pressure for two-way water valve applications shall be the shutoff head of associated pump.  Required close-off rating of steam valve applications shall be design inlet steam pressure plus 50 percent for low pressure steam, and 10 percent for high pressure steam.  Required close-off rating of air damper applications shall be shutoff pressure of associated fan, plus 10 percent.
     • Manufacturer shall provide a 2 year unconditional warranty from date of substantial completion.
     • Sound levels for VAV actuators shall not exceed 45 dB.
     • Electronic overload protection shall protect actuator motor from damage. If damper jams actuator shall not burn-out. Internal end switch actuators are not acceptable.
     • Subject to compliance with requirements, approved manufacturers are as follows: <Confirm list>
       • Honeywell
       • Siemens
       • Johnson Controls
       • Approved equal

  3. Control Dampers Actuators:

     1. OA (outside air), RA (return air), and EA (exhaust air) actuators shall be spring return type for safety functions. Individual battery backup or capacitor return is not acceptable. With approval a central battery pack NSV system similar to a UPS system may be used with a battery checking circuit to the DDC automation system. Daily verification of battery performance shall be incorporated in the programming.
     2. The control circuit shall be fully modulating using 2-10 volt or 4-20 mA signals. Accuracy and repeatability shall be within ± 1/21 of control signal. A 2-10 v or 4-20 mA signal shall be produced by the actuator which is directly proportional to the shaft clamp position which can be used to control actuators which are paralleled off a master motor or to provide a feedback signal to the automation system indicating damper position. Accuracy shall be within ±5%.
     3. Stroke: 90 seconds end to end full stroke, 15 seconds return to normal for spring return, field selectable rotational/spring return direction.
     4. Rating: NEMA 2 Enclosure.
     5. Manual override with field adjustable zero and span.
     6. Duty cycle: rated for 65,000 cycles.
     7. Face and bypass dampers and other control dampers shall be modulating using the same control circuit detailed above but shall not be spring return.

  4. Miscellaneous Damper Actuators:

     • OA combustion and ventilation air intake and EA damper actuators shall be 2 position spring return closed if any water piping, coils or other equipment in the space which the damper serves needs to be protected from freezing. Otherwise drive open, drive closed type 2 position may be used. The minimum torque for any actuator shall be 5 N-m.
     • Provide auxiliary switches on damper shaft or blade switch to prove damper has opened on all air handling equipment handling 100% outside air and greater than 6 KPa TSP.

  5. Air Terminals:

     • Air terminal actuators shall be minimum 5 N-m torque and use fully modulating, floating (drive open, drive closed), 3 wire control or use control circuit as detailed in control dampers depending on the controller’s requirements. Noise level shall not exceed 45dB. Life cycle shall be a minimum of 60,000 cycles and 1.5 million repositions. Actuator Power consumption shall not exceed 4VA.

  6. Inlet Vanes Actuators:

     • Inlet vane actuators shall provide at least 150% of the minimum torque specified by the manufacturer as necessary to operate vanes properly. Either direct coupled or gear train with linkages are acceptable as required.  The control loop for static control of the actuator shall operate slowly enough to avoid hunting and maintain stable control.

  7. Combination Smoke and Fire Damper Actuators:

     1. 1. Actuators shall be connected to the damper section and shall conform to UL 555S specifications. Control requirements shall meet UL K 864 smoke requirements.

  8. Control Valve Actuator General Requirements

     1. Electric:

        • Motor: Suitable for 120 or 240 volt single-phase power supply.  Insulation shall be NEMA Class F or better.  Motor shall be rated for 125 percent duty cycle.  Motors shall have inherent overload protection.
        • Gear Train: Motor output shall be directed to a self-locking gear drive mechanism.  Gears shall be rated for torque input exceeding motor locked rotor torque.
        • Wiring: Power and control wiring shall be wired to a terminal strip in the actuator enclosure.
        • Failsafe Positioning: Actuators shall be spring return type for failsafe positioning.
        • Enclosure: Actuator enclosure shall be a NEMA 4 epoxy coated metal enclosure, and shall have a minimum of two threaded conduit entries.
        • Limit Switches: Travel limit switches shall be UL approved.  Switches shall limit actuator in both open and closed positions.
        • Mechanical Travel Stops: The actuator shall include mechanical travel stops of stainless steel construction to limit actuator to specific degrees of rotation.
        • Manual Override: Actuators shall have manual actuator override to allow operation of the valve when power is off.  For valves 4 inches and smaller the override may be a removable wrench or lever or geared handwheel type.  For larger valves, the override shall be a fixed geared handwheel type.  An automatic power cut-off switch shall be provided to disconnect power from the motor when the handwheel is engaged for manual operation.
        • Valve Position Indicator: A valve position indicator with arrow and open and closed position marks shall be provided to indicate valve position.
        • Torque Limit Switches: Provide torque limit switches to interrupt motor power when torque limit is exceeded in either direction of rotation.
        • Position Controller: For valves used for modulating control, provide an electronic positioner capable of accepting 4-20 mA, 0-10 VDC, 2-10 VDC, and 135 Ohm potentiometer.
        • Ambient Conditions: Actuator shall be designed for operation from –140 to 150 degrees F ambient with 0 to 100 percent relative humidity.
        • Field selectable direction with field adjustable zero span.

     2. Pneumatic Single- and Double-Acting Cylinder Type:

        • Air Cylinder: Shall consist of steel or aluminum cylinder, dual pistons, double rack and pinion gearing mechanism.  Housing shall be protected both internally and externally with corrosion resistant coating.  Actuator shall be equipped with piston guide rods or similar mechanism so that seals are not loaded as linear bearings.  Single acting units shall have multiple symmetrically arranged springs to apply equal force to piston.  Cylinder shall be configurable for direction of fail-safe mode in the field.  Actuators shall be spring return type for failsafe positioning.
        • Position Indication: Provide extended shaft position indicator that is removable for manual override of valve.
        • Two-Position Actuators: Provide appropriate three-way or four-way solenoid valve mounted on the actuator.  Solenoid valve electrical enclosure shall meet NEMA 4 requirements.  Provide actuator with position switches where required.
        • Modulating Actuators: Provide a rotary electronic positioner designed to accept 4-20 mA, 0-10 VDC, 2-10 VDC, or 135 Ohm potentiometer and operate integral 3-way or 4-way solenoid valve to position valve rotation angle as sensed by integral position feedback device to match signal input.  Enclosure shall meet NEMA-4 requirements.  Actuator linearity and resolution shall be 0.5 percent of span.  Hysteresis and deadband shall be adjustable.  Provide accessory mechanical or proximity type position switches and position transmitters where required.  Actuators shall be spring return type for failsafe positioning.  Provide an enclosure heater for positioners located outside of buildings.  Coordinate power and electrical wiring for heater.

  9. Electric Control Valves Actuators 4 inches and larger:

     • The valve actuator shall consist of a permanent split capacitor, reversible type electric motor which drives a compound epicycle gear. The electric actuator shall have visual mechanical position indication, readable from a distance of 25 feet, showing output shaft and valve position.  Unit shall be mounting directly to the valves without brackets and adapters, or readily adapted to suit all other types of quarter-turn valves.
     • The actuator shall have an integral terminal strip, which, through conduit entries, will ensure simple wiring to power supplies. Cable entries shall have UL recommended gland stops within the NPT hole to prevent glands from being screwed in too far and damaging cable.
     • The actuator shall be constructed to withstand high shock and vibrations without operations failure. The actuator cover shall have captive bolts to eliminate loss of bolts when removing the cover from the base.  One copy of the wiring diagram shall be provided with the actuator.
     • The actuator shall have a self-locking gear train which is permanently lubricated at the factory. The gearing shall be run on ball and needle bearings.  Actuators with 620 in-lb or more output torque shall have two adjustable factory calibrated mechanical torque limit switches of the single-pole, double-throw type.  The motor shall be fitted with thermal overload protection.  Motor rotor shaft shall run in ball bearings at each end of motor.
     • For intermittent on/off service, the actuator shall be rated at a 20% duty cycle (i.e., 12 minutes extended duty in every hour, or alternatively; one complete cycle every 2 minutes). For more frequent cycling and modulating service, an actuator shall be rated for continuous duty.  The actuator rated for continuous duty shall be capable of operating 100% of the time at an ambient temperature of 105°
     • The actuator shall have an integral self-locking gear train. Motor brakes shall not be required to maintain desired valve position.  Levers or latches shall not be required to engage or disengage the manual override.  Mechanical travel stops, adjustable to 15° in each direction of 90° rotation shall be standard, as well as two adjustable travel limit switches with electrically isolated contacts.  Additional adjustable switches shall be available as an option.
     • Single Phase Motor: The motor shall have Class B insulation capable of withstanding locked-rotor for 25 seconds without overheating.  Wiring shall also be Class B insulation.  An auto-reset thermal cut-out protector shall be embedded in the motor windings to limit heat rise to 175°F in a 105°F ambient.  All motors shall be capable of being replaced by simply disconnecting the wires and then removing mounting bolts.  Disassembly of gears shall not be required to remove the motor.
     • Materials of Construction: The electric actuator shall have a pressure die-cast, hard anodized aluminum base and cover.  The compound gear shall be made of die-cast, hard anodized aluminum or steel.  An alloy steel worm gear shall be provided for manual override and torque limiting.  Bearings for gears shall be of the ball and needle type; bronze bearings shall be used on the shafting parts.
     • Torque: Size for minimum 150% of required duty.
     • Potentiometer for providing continuous feedback of actuator position at the controller (for valves specified position feedback).