SAMPLE SPECIFICATION: HARD WIRED Carbon Monoxide (CO) DETECTION SYSTEM
1. General
The work covered by this section includes the Procurement and installation of a Gas Detection System and related components as described herein and as shown on the contract drawings. The major items of work to be included are:
1.1. installation of a central control panel(s) as located on the contract drawings,
1.2. provide required electrical connections for 120 VAC power feed,
1.3. provide interconnect components for exhaust/supply fan control,
1.4. provide central control panel annunciation interconnect wiring as described herein,
1.5. installation of (*ENGINEER TO ADD CO SENSOR COUNT HERE*) sensors as shown on the drawings,
1.6. installation of signal cabling and conduit between the sensors and control panel,
1.7. provide calibration accessories for start-up and commissioning services by Manufacturer Authorized or certified Technician.
The CO/NO2 Gas Detection System shall be a hard-wired system employing diffusion style gas detection method. The MSA ZGard family of Products as manufactured by MSA and represented by Mechanical Technologies, Pompton Plains, NJ or Manhattan, NY
2. Submittals
2.1. Product data: Submit specific product literature for all materials.
2.2. Submit Installation, Outline, Dimensional and planned wiring Drawings.
2.3. Provide certification of Manufacturer’s Authorized Start up Agent or Certified Technician.
3. Central Control Panel
3.1. The control panel shall provide a scanning illuminated display showing the sensor number and parts per million (ppm) level for each sensor in sequential order, and shall provide an LED indication of sensor and system status, “sensor ok", "warning", “Sensor Failure” and "alarm".
3.2. The control panel shall include auto-configuration upon power up that digitally recognizes all remote devices on the network and assigns a network node value.
3.3. The control panel shall include an internal user programmable internal audible alarm with local and remote push-button reset capability.
3.4. The control panel enclosure shall be rated for General Purpose use and constructed of painted steel construction with hinged door secured by tamper resistant screws.
3.5. The control panel shall operate on 120 VAC, 50/60 Hz power and include internal power supply capable of powering all remote devices communicating with the central control panel via four conductor shielded cable(s).
3.6. The central panel cabinet shall include a common warning, alarm, system fault and annunciation relay for external audible/visual device.
3.7. The central panel shall include field programmable zone control capability via 12 user programmable relays, expandable to 126, to improve fan activation sequence.
3.8. The central panel shall incorporate a programmable on/off time delay to minimize fan oscillation when the detected levels of gas reach the threshold activation value of the control point for the fan interlocks.
3.9. The central shall have the capability to accommodate a unit mounted Strobe Tower or remotely mounted Horn Strobe Tower that can be activated and via any of the provided relay contacts.
4. Carbon Monoxide Sensor/Transmitters
4.1. The CO sensor transmitter shall have a full scale detection range of 0-200 part per million (ppm) full scale.
4.2. The Sensor Transmitter will employ a long-life electro-chemical based technology gas detection element that is precision mounted via sockets directly to the electronics to facilitate calibration and easy replacement.
4.3. The Sensor Transmitter shall be constructed of a General Purpose Metal cover Plate to protect against vandalism and accidental damage and installed on a flat surface 4”’x 4” metal or PVC enclosure with 3/4” PVC conduit fitting. Optional NEMA 4X enclosure is available for sites where weather elements may impact product performance.
4.4. Sensor Transmitter shall include an output signal verification jumper that is user selectable to half scale or full scale output to simulate gas detection reading and communication with central control panel without the use of calibration gas.
4.5. The Sensor Transmitter shall work by the diffusion principle with no need for external devices to condition or enhance movement of the atmosphere within the area being monitored.
4.6. The Sensor Transmitter shall be microprocessor-based capable of digital communication via RS-485 output via 4-conductor (2 power, 2 data) #16 AWG cable (multiple drops on a single cable).
4.7. Cable and Conduit. The contractor shall furnish and install 4-conductor, #16 AWG shielded cable per local codes between sensor/transmitters and control panel as shown on the drawings. Multiple Trunk lines up to four maximum are permissible. Final wire gage shall be determined by trunk line distance.
4.8. Exhaust/Supply Fan Interlocks and Central Alarm Interlock, Engineer to define description of interlocks between Carbon Monoxide detection system and exhaust fans and alarms and any interface to BMS.
4.8.1. SAMPLE CONTROL SCENARIO ONLY
4.8.1.1. The CO detection system shall provide control of the exhaust and supply fans per the contract drawings, and shall be capable of sending a central alarm signal to the building automation/alarm system upon the following detection level sequence:
CARBON MONOXIDE
4.8.1.2. For Carbon Monoxide gas levels below 25ppm - Exhaust/Supply Fans are OFF.
4.8.1.3. At a Carbon Monoxide gas level value 25ppm, Exhaust/Supply Fans ON and remain on until value falls below 25ppm for 5 minutes. A
4.8.1.4. At a continued increasing value of Carbon Monoxide gas level >50% full scale, Central Panel Audible/visual alarm and any external audible and visual strobes activate. Exhaust/Supply Fans ON High and remain ON for 5 minutes after alarm set point decreases below 25ppm alarm level plus an additional 5 minute off delay.
4.8.1.5. For Nitrogen Dioxide gas levels below 2.5ppm - Exhaust/Supply Fans are OFF.
NITROGEN DIOXIDE
4.8.1.6. At a Nitrogen Dioxide gas level value >2.5ppm, Exhaust/Supply Fans ON and remain on until value falls below 25ppm for 5 minutes.
4.8.1.7. At a continued increasing value of Nitrogen Dioxide gas level >50% full scale, Central Panel Audible/visual alarm and any external audible and visual strobes activate. Exhaust/Supply Fans ON High and remain ON for 5 minutes after alarm set point decreases below 2.5ppm alarm level plus an additional 5 minute off delay.
5. Calibration Kit and Test Gases
5.1. The CO and/or NO2 detection system manufacturer shall provide a complete test kit with sufficient NIST Traceable test gas to allow for all commissioning tests and scheduled calibrations following initial start-up.
6. Start-up and Training Service
6.1. Project scope may include the following for large systems. The Contractor shall make available the services of the manufacturer's factory technician to inspect the system installation, complete a thorough test and calibration of the system, and provide minimum of 2 hours training to the owner’s personnel.