Temperature Sensors Technical Requirements for Integrated Automation System

This article is about general and technical requirements for differential pressure transmitter (DP Transmitter) used in Integrated Automation System or Building Automation System.

Temperature Sensors Technical Requirements for Integrated Automation System

• TEMPERATURE SENSORS (TS) <Modify as required to match project design>
  1. Sensor range: When matched with A/D converter of PCU/ASC, or SD, sensor range shall provide a resolution of no worse than 0.3 degrees F (0.16 degrees C) (unless noted otherwise). Where thermistors are used, the stability shall be better than 0.25 degrees F over five (5) years.
  2. Matched Sensors: The following applications shall require matched sensors:
     1. Hydronic Temperature Difference Calculations: Provide matched supply and return temperature sensors where the pair is used for calculating temperature difference for use in load calculations or sequencing such as across chillers and plants.  Sensing element shall be platinum RTD guaranteeing an accuracy of +/- 0.5 percent of span plus 0.1 degrees C.
     2. Air Handling Unit Sequencing: Provide matched pair for the cooling and heating coil leaving sensors where the sequence includes calculating an offset from the supply air setpoint to maintain a leaving heating coil temperature. Sensing element shall be platinum RTD guaranteeing an accuracy of +/- 0.5 percent of span plus 0.1 degrees C.
  3. Room Temperature Sensor: Shall be an element contained within a ventilated cover, suitable for wall mounting, unless noted otherwise.  Provide insulated base.  The following sensing elements are acceptable:
     1. Sensing element shall be thermistor (10K Ohm, Type II), +/- 0.2 degrees F accuracy at calibration point (10,000 Ohms @ 77 °F).
     2. Sensing element shall be mounted in a beige colored plastic enclosure
     3. Operating Temperature Range: -40 to 302 °F (-40 to 150 °C)
     4. Operating Humidity Range: 0 to 90% RH non-condensing
     5. <Provide setpoint adjustment where indicated. The setpoint adjustment shall be a warmer/cooler indication that shall be scalable or limited via the IAS.>
     6. <Provide an occupancy override button on the room sensor enclosure where indicated. This shall be a momentary contact closure.>
     7. <Provide current temperature indication via an LCD or LED readout, where noted.>
     8. Submit sensor to Architect for aesthetic and finish approval prior to installation.
     9. Acceptable Manufacturers <Confirm list>
     10. Approved equal
  4. Critical Room Temperature Sensor: Shall be an element contained within a ventilated cover, suitable for wall mounting.  Provide insulated base.  The following sensing elements are acceptable:
     • • Sensing element shall be platinum RTD, +/- 0.1 degrees C measured at 0 degrees C.
       • <Provide setpoint adjustment where indicated. The setpoint adjustment shall be a warmer/cooler indication that shall be scalable via the IAS.>
       • <Provide an occupancy override button on the room sensor enclosure where indicated. This shall be a momentary contact closure.>
       • <Provide current temperature indication via an LCD or LED readout, where noted.>
  5. Standard Single-Point Duct Temperature Sensor: Shall consist of sensing element, junction box for wiring connections and gasket to prevent air leakage or vibration noise. Temperature range as required for resolution indicated.  Sensor probe shall be 316 stainless steel.
     • Sensing element shall be thermistor (10K Ohm, Type II), +/- 0.2 degrees F accuracy at calibration point (10,000 Ohms @ 77 °F).
     • Sensing element shall be encased in 4” or 8” stainless steel probe
     • Operating Temperature Range: -40 to 302 °F (-40 to 150 °C)
     • Operating Humidity Range: 0 to 90% RH non-condensing
     • Sensor stability +/- 0.13 °C Duct mount sensors shall mount in a hand box through a hole in the duct and be positioned so as to be easily accessible for repair or replacement. A neoprene grommet (sealtite fitting and mounting plate) shall be used on the sensor assembly to prevent air leaks.
     • For outdoor air duct applications, use a weatherproof mounting box with weatherproof cover and gasket.
     • Acceptable Manufacturers <Confirm list>
     • Approved equal
  6. Critical application Single-Point Duct Temperature Sensor: Shall consist of sensing element, junction box for wiring connections and gasket to prevent air leakage or vibration noise. Temperature range as required for resolution indicated.  Sensor probe shall be 316 stainless steel.
     • Sensing element shall be platinum RTD, +/- 0.1 degrees C measured at 0 degrees C.
     • Duct mount sensors shall mount in a hand box through a hole in the duct and be positioned so as to be easily accessible for repair or replacement. A neoprene grommet (sealtite fitting and mounting plate) shall be used on the sensor assembly to prevent air leaks.
     • For outdoor air duct applications, use a weatherproof mounting box with weatherproof cover and gasket.
     • Acceptable Manufacturers <Confirm list>
       • Honeywell
       • ACI
       • Pre Con
       • JCI
       • Schneider
       • Siemens
       • BAPI
       • Distech
       • Approved equal
  7. Standard Averaging Duct Temperature Sensor: Shall consist of an averaging element, junction box for wiring connections and gasket to prevent air leakage. Provide sensor lengths and quantities to result in one lineal foot of sensing element for each three square feet of cooling coil/duct face area, or as recommended by manufacturer.  Temperature range as required for resolution indicated.
     • Sensing element shall be thermistor (10K Ohm, Type II), +/- 0.2 degrees F accuracy at calibration point (10,000 Ohms @ 77 °F).
     • Sensing element shall be encased in 8’ (4 sensing points), 12’ (4 sensing points) or 24’ (9 sensing points) long bendable copper sheath
     • Operating Temperature Range: -40 to 302 °F (-40 to 150 °C)
     • Operating Humidity Range: 0 to 90% RH non-condensing
     • Sensor stability +/- 0.13 °C
     • Provide capillary supports at the sides of the duct / coil to support sensing elements
     • Averaging Sensor shall traverse the width of the duct.
     • Acceptable Manufacturers <Confirm list>
     • Approved equal
  8. Liquid immersion temperature sensor shall include brass thermowell, sensor and connection head for wiring connections. Temperature range shall be as required for resolution of 0.15 degrees
     • Sensing element (chilled water/glycol systems) shall be platinum RTD +/- 0.2 degrees C measured at 0 degrees C.
  9. Pipe Surface-Mount Temperature Sensor: Shall include metal junction box and clamps and shall be suitable for sensing pipe surface temperature and installation under insulation. Provide thermally conductive paste at pipe contact point. Temperature range shall be as require for resolution indicated in this Section.
     • Sensing element shall be platinum RTD, thermistor, or integrated circuit, +/- 4 degrees F accuracy at calibration point.
  10. Outside Air Sensors shall consist of a sensor, sun shield, utility box, and watertight gasket to prevent water seepage. Temperature range shall be as require for resolution indicated in this Section.
      • Sensing element shall be thermistor (10K Ohm, Type II), +/- 2 degrees F accuracy at 0 to 70 °F.
      • Sensing element shall be encased in a weather proof enclosure which shall be designed to withstand the environmental conditions it will be exposed.
      • Provide a solar shield
      • Operating Temperature Range: -40 to 302 °F (-40 to 150 °C)
      • Operating Humidity Range: 0 to 90% RH non-condensing
      • Sensors exposed to wind velocity pressures shall be shielded by a perforated plate surrounding the sensor element.
      • Temperature transmitters shall be of NEMA 3R construction and rated for ambient temperatures.
      • <Solar load sensors shall be provided in locations shown. The use of a thermistor combined with a solar compensator is acceptable.  Provide calibration charts as part of the O&M Manual.>
      • Acceptable Manufacturers <Confirm list>
      • Approved equal
  11. Freezestats shall be installed along the entire face of each hot or cold water coil located in areas where freezing temperatures could be encountered (mixed air chambers, makeup air units etc). The sensing element shall evenly cover the entire coil surface. A minimum of 1 linear foot of element shall cover each 1 square foot of the coil element. Freezestats shall contain double pole switches and shall require a manual reset when a freezing condition is encountered. One pole of the freezestat shall be directly hardwired to the AHU fan system to disable it. The second pole shall be utilized to report he condition to the IAS.