I.GAS DETECTION EQUIPMENTAND SERVICES GENERAL
A.The gas detection equipment consists of
1.Analyzer / Transmitters
2.Gas Sensors and ancillary mounting hardware
3.Receiver / Controller(s) for local Annunciation or Alarms and Outputs to SCADA System
4.Sample Draw and Conditioning Equipment and Accessories
5.Consumables, Spares, Commissioning Warranty and Miscellaneous
B.The gas detection equipment furnished under this specification must comply with the American Recovery and Reinvestment Act and be so certified by the manufacturer. Reference§1605 of the American Recovery and Reinvestment Act, Interim Rule subpart 26.5, Volume 74, Federal Register 14623-33, March 31, 2009,Made in the United States provision.
C.All equipment furnished under this specification must meetthe requirements of NFPA 820 and be installed in accordance with NFPA 70, the National Electrical Code (NFPA 70), and the Standards of the (Insert appropriate AHJ).
D.All Combustible gas, Toxic gas, and Oxygen detection instruments shall be products of the same manufacturer and willhave the most current version of hardware and firmware. The firmware shall include predictive “Sensorend-of-life” warning at 10% remaining life, indicated locally at theTransmitter and remotely viaa configurable AlarmRelay or fault current on the 3-Wire 4-20mA,24 VDC signal loop. The “end-of-life” function shall be based on at least three of the following parameters: 1) cumulative gas exposure, 2) calibration gain, 3) Sensor power-on hours4) Sensor age. The Sensorshall not be disabledafter the end-of-life warning occurs.
E.The Sensor head and interface shall be certified Intrinsically Safe to enable Sensor hot-swap in-field replacement without requiring powering down of the Transmitter, declassifying the area or compromising the hazardous (classified) area safety. A copy of the Approval agency control drawing showing Intrinsic Safety Approval and live maintenance remote Sensor capability in a Class I, Division 1, Group A through F areas must be submitted.
F.The Receiver / Controller shall have four (4) input channels and automatically recognize and configureforthe connected gas detection equipment to display the correct gas name or type, range, measuring units and default Alarm values of that gas or gases with mixed input gas types. In the event of power failure, the system will automatically reconfigure and resume operation.
G.The gas detection vendor will provide a factory certified technicianfor system start-up.
H.The gas detection Transmitters and Sensors shall be FM or ATEX approved for Class I and II, Divisions 1 and 2, Groups A B C D E F & G, as manufactured by Sensidyne, LP.
II.ANALYZER / TRANSMITTER ASSEMBLY
A.Thesame part number UniversalTransmittershall be usedforall Toxic gas, Combustibles (gas or vapor), and Oxygen Sensors, to streamline calibration, operational maintenance procedures and to reduce spare parts inventory.
1.The Transmitter shall have a large 5-line backlit LCD display with 0.5 inch characters and will display gas name or type, range, measuring units, Sensor diagnostics and the Transmitter interface and configuration menus. The Transmitter menus and messages shall be in plain English. Look-up codes are not permitted.
2.The Transmitter shall be equipped with one configurable and assignable SPDT Alarm Relay. An option to add three SPDT fully configurable and assignable Relays,integral to the Transmitter, shall be available. All relays must be configurable for energized state, latching or non-latching operation and dead-band. Relays must be dry contact SPDT rated at 5 Amps, 115 VAC.
3.For enhanced maintenance capability, fully configurable and assignable fault currents on the 4-20mA DC loop shall be available for allAlarm and failure conditions includingGeneral Fault, Head Fail, Missing Sensor, Sensor Fail, Sensor End-of-Life, Output Current Track, Calibration Mode, Maintenance Mode, ToD Fail, and ToD End-of-Life.
4.The Transmitter shall have areal time clock so that all critical event data can be time and date stamped. This includes but is not limited to Calibration, Test-on-Demand, gas exposure and TWA Alarms
5.Communications including HART or RS 485 (Modbus Protocol) must be available integral to the Transmitter. All communications must be fully configurable for address, parity and other attributes.
6.The Transmitter shallautomatically recognize the plugged in Sensor and configure with Alarm values, calibration data and predictive Sensor lifedata from Sensor memory. The date of the last calibration and other time-stamped information, including gas exposure and TWA Alarms shall be availablethrough the non-intrusive interface.
7.The analyzer/Transmitter shall be capable of being direct mounted to the Intrinsically Safe Sensor interface or remote mounted with cable only up to 100 Feet away without compromising hazardous (classified) area safety. A remote mounting kit with Sensor bracket and duct mounting kit with all hardware shall be furnished as referenced in the drawings.
8.The Transmitter enclosure shall be Copper-free cast Aluminum with an anodized Aluminum or PVC Sensor Head.
9.The Transmitters shall be SensAlert PLUS as manufactured by Sensidyne, LP.
III.GAS SENSORS: TOXICS AND OXYGEN
A.Sensors for Toxicgases and Oxygen shall be designed to retain bench calibration thus allowing for in-field replacement. The Transmitter interface shall be FM certified Intrinsically Safeto enable Sensor hot-swap, in-field replacement without requiring powering down of the Transmitter, declassifying the area or compromising the hazardous (classified) area safety.
B.Sensors for Toxic gases and Oxygen shall operate in 15–90 %RH and intermittently to 99% RH, (non-condensing), employcontinuous active temperature compensation (-40° to 50°C (-40° to 122°F))and have nonvolatile memory for gas name or type, span, Alarm values, exposure history, Sensorremaining life factors and calibration data.
C.The Toxic gas (H2S) Sensors shall be “smart” diffusion–type, electro-chemical with an expected service life of 2 years minimum and, a 14 month non-pro-ratedwarranty from the date of installation, not to exceed 20 months from shipment. The Transmittershall provide a 4-20mA DC linear output over a 0 – 100 (50) ppm range.
D.The H2S Sensor assembly shall include an integral gas generation cell to provide test-on-demand (ToD) to ensure that the Sensor is operational and responsive. The ToD function shall be capable of manual initiation from the Transmitternon-intrusiveinterface or performed automatically at user selected times and frequency. The option of placing the Transmitter in maintenance mode shall be provided to avoid Alarming when ToD is performed. Notification of TOD result shall be communicated via aconfigurable 4-20mA fault indication signal or assignable to a Relay.
E.The Oxygen Sensor shall be a “smart,” fail-to-safe, Galvanic electro-chemical type with an expected service life of 14 Months minimum and, a 14 Month non-pro-rated warranty from the date of installation, not to exceed 20 months from shipment. The Transmitter shall provide a 4-20mA DC linear output over a 0 – 25% by volume range.
F.The Oxygen and Hydrogen Sulfide Sensors shall be FM Performance certified and the sensor datasheets shall be submitted with the FM approval logo.
IV.GAS SENSORS: COMBUSTIBLE GAS AND VAPOR
A.Combustible gas and vapor Sensors shall be designed to retain bench calibration thus allowing for in-field replacement. The Transmitter interface shall be FM certified Intrinsically Safe to enable Sensor hot-swap, in-field replacement without requiring powering down of the Transmitter, declassifying the area or compromising the hazardous (classified) area safety.
B.Combustible gas and vapor Sensors shall operate in 15–99% RH, (non-condensing), employ continuous active temperature compensation (-25° to 75°C (-13° to 167°F)) and have nonvolatile memory for gas name or type, span, Alarm values, exposure history, Sensor life factors, K-factor, calibration gas value and actual span / zero calibration data.
C.The Combustible gas and vapor sensor shall be a plug-in dual wavelength smart Infrared absorptiontype which does not require Oxygen for operation and cannot be poisoned or inhibited by Sulfur, Lead or Silicone compounds. The Infrared Sensor shall be FM performance certified and fail-to-safe (Fault) with no circumstances where it will not respond to gas. The sensor datasheet shall be submitted with the FM logo.
D.The Infrared Combustibles Sensor shall have an expected service life of 5 years and, a 2 year non-pro-rated warranty from the date of installation, not to exceed 30 months from shipment. The Transmitter shall provide a 4-20mA DC linear output over a 0 – 100% LEL range.
E.CombustiblesGas Sensor/analyzer/Transmitter equipment shall be SensAlert Plus, as manufactured by Sensidyne, LP.
V.RECEIVER / CONTROLLER
A.The Receiver / Controller shall automatically recognize and configure for the connected gas detection equipment to display the correct gas name or type, range, measuring units and default Alarm values of that gas or gases with mixed input gas types. In the event of power failure, the system will automatically restart, reconfigure and resume operation.
B.The Controller shall have four (4)3-Wire, 4-20 mA input channels, be equipped with a Red, Double-flash high recognition Strobe-light, a 90 dB Sounder and a Reset Pushbutton for latched Alarms or Calibration mode alarm inhibit. It shall be housed in a NEMA 4X, UL listed Polycarbonate enclosure.
C.Local discrete Displays shall be provided for each input channel for the monitored gas Value (0.75 inch, 3 Digit LED)and for the gas name or type and measuring units (0.5 LCD display).
D.The system shall have three (3) SPDT AlarmRelaysfor each input channel and a common Fault Relay. Four(4) LEDs per channel shall provide visual Channel Alarm status. Discrete 4-20 mA and RS-485, Modbus Protocol, outputs will be provided.
E.All Relay contacts shall be rated at 5 Amps, 115 VAC, 50/60 Hz. The Controller shall be powered by 24 VDC, or 115/230 VAC, 50/60 HZ
VI.PUMPED SAMPLE-DRAW SYSTEM
A.A pumped or aspirated sample draw system shall be furnished to draw a sample from the wet well(s) up to 75 Feet away. Sample flow shall be a nominal 1 LPM with a sample flow fault Relay set at 0.6 LPM nominal flow rate. A 3-way valve for the introduction of calibration gas shall be provided. The unit shall be modular in design and suitable for placement in a Class I, Division 2 area for sampling from a Class I, Division 1, Groups C & D hazardous (classified) area. Hard plastic or metal tubing (0.25 or 0.375 inch inside diameter) shall be used. Tygon is not acceptable. Wet well application sample conditioning and flame trap accessories shall be provided.
VII.CONSUMABLES, SPARES, COMMISSIONING, WARRANTY AND MISCELLANEOUS
A.One spare consumable shall be furnished for each consumable in the gas detection system, but not including gas sensors.
B.Calibration equipment consisting ofa carrying case and regulator with tubing shall be furnished complete with a one year’s supply of zero and span gases for all the sensors in the pumping station.
C.One Transmitter of each type shall be furnished as a spare.
D.Alist of other recommended spares shall be provided with pricing valid for one year from the start-up date of the equipment on this project.
E.The gas detection vendor will provide a factory certified technician for the following:
1.Wiring verification
2.System commissioning
3.Training of owner’s or service firm’s personnel
F.Stainless steel tags shall be provided for each separate item furnished, except consumables.
G.An extended warranty to allow for equipment installation time shall be provided, consisting of up to 4 months extension but not more than 18 months after shipment for sensors and 28 months after shipment for all electronic items. Instrument shipment to the worksite shall be coordinated and Gas Sensor shipment may be delayed at the discretion of the contractor and supplier.
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