1、A-A-50624 m 9999974 0364820 080 m A-A-50624 9 June 1994 COMMERCIAL ITEM DESCRIPTION AIRFLOW MONITORING EQUIPMENT The General Services Administration has authorized the use of this commercial item description in preference to MIL-S-16032M. Abstract. This Commercial Item Description covers requirement
2、s for airflow monitoring equipment that measures and provides a display of airflow velocity, and generates alarms whenever airflow velocity drops below a predetermined level. Integral components include an airflow sensor and an associated airflow display panel. The equipments are intended for use in
3、 virtually any air ventilation system including those which service hazardous material stowage compartments where impeded airflow could result in dangerous conditions. Salient characteristics. 1. Airflow monitoring svstem. The detailed requirements for airflow sen- sors and airflow display panels bu
4、ilt in accordance with this CID are described in sections (2) and (3) below respectively. The basic performance requirements of an airflow monitoring system comprised of an airflow sensor and airflow display panel built in accordance with this CID are as follows: a. Range. The airflow system shall a
5、ccommodate selectable subranges within an overall airflow range of from O to 50 meters per second (mps). b. Accuracv. Airflow velocity measurement accuracy shall be within f (3.0 percent of reading plus 2.0 percent of full-scale). Low-airflow alarm point detection accuracy shall be within: rt (6.0 p
6、ercent of the selected low-airflow point plus 1.0 percent full-scale). I 1 Beneficial comments, recommendations, additions, deletions, clarifications, etc. and any other data which may improve this document should be sent by letter to: Commander, Naval Sea Systems Command, ATTN: SEA 05442, 2531 Jeff
7、erson Davis Hwy., Arlington, VA 22242-5160. FSC 6680 AMSC N/A DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Licensed by Information Handling ServicesA-A-50624 c. Response time. When operated in a standard one-atmosphere ambient environment with an airflow velocity
8、 of 25 percent of full-scale, the airflow monitoring system shall achieve a full-accuracy output signal and full-accuracy display readout within 12 seconds for an airflow velocity step increase of from 30 to 75 percent full-scale. d. Repeatability. Airflow monitoring system repeatability shall be to
9、 within tr 1.5 percent of full-scale. 2. Airflow sensor. a. Required operating: principle. The sensor shall employ a thermal anemometer technique for sensing airflow. b. Physical characteristics. The sensor shall consist of a cylin- drical probe and an attached/integral electronics processing packag
10、e. The sensor probe shall be constructed of corrosion resistant material. shall be from 1.0 cm to 2.6 cm in outside diameter. appropriate for the cylindrical or rectangular duct size as specified. A mounting plate shall be provided to secure the sensor to the air duct. The sensor shall be readily re
11、movable from the mounting plate (to facilitate periodic cleaning). The sensor probe The probe length shall be c. Power input. The airflow sensor shall be powered by +15 to +18 Vdc and shall draw no more than 350 mA. d. Airflow Range. The airflow velocity range of the sensor shall be from zero mps to
12、 the full-scale mps value as specified. e. Output signal. The airflow sensor shall output a 4-20 mA signal linearly proportional to airflow velocity. A 4 mA output shall correspond to zero airflow velocity and a 20 mA output shall correspond to full-scale airflow velocity. The sensor shall drive a r
13、esistive load of 250 ohms t 5 percent. f. Accuracy. The airflow velocity output signal shall be accurate to within f (3.0 percent of reading plus 1 percent of full-scale). g. Repeatability. Repeatability shall be to within i 0.5 percent of full-scale. h. Response time. velocity change. When operatin
14、g in a standard one- atmosphere environment and an airflow velocity of 25 percent full-scale; the airflow sensor shall achieve a full-accuracy output signal within 10 seconds for an airflow velocity step increase to 75 percent full-scale, i. ResDonse time. temperature change. When operated in a stan
15、dard one-atmosphere environment and an airflow velocity of 50 percent full-scale; the airflow sensor shall achieve a full-accuracy output signal within four minutes for a 20 degrees Celsius (OC) temperature step increase. 2 Licensed by Information Handling ServicesA-A-50624 9999974 OLL14822 953 A-A-
16、 50624 j. Interface with airflow disDlav Danel. The airflow sensor shall connect to the airflow display panel via a three-conductor cable of a length as specified. One conductor shall carry the airflow signal, one conductor the dc power, and one shall be a common conductor. The cable shall be detach
17、able from the airflow sensor via an accessible screw-lug terminal located inside the airflow sensor assembly. The screw-lugs shall be marked as to function. k. Reliabilitv. The airflow sensor minimum mean time between failures (MTBF) shall be no less than 25,000 hours. 1. Safety (hazardous environme
18、ntl. The airflow sensor shall be in compliance with the NEC requirements for safe use in Class I, Division 2, Group D hazardous locations. 3. Airflow disDlay Danel a. Physical Characteristics. The airflow display panel shall not exceed the following outside dimensions: 33 cm in width, 28 cm in heigh
19、t, and 25.4 cm in depth (including any attached mounting pads). bulkhead mountable via the hole pattern as specified. matching the panel to the specified hole-pattern may be used.) The panel shall be corrosion resistant. The panel shall incorporate a swing-open panel door with an identification plat
20、e affixed on the outside of the panel door and labeled as indicated. The panel shall be (An adapter plate for b. Range. The airflow range of the panel shall be manually selectable. Selectable ranges shall include: O - 1 mps O - 2.5 mps O - 5 mps O - 10 mps O - 25 mps O - 50 mps c. Input signal. The
21、airflow panel shall accept a 4-20 mA signal linearly proportional to airflow velocity. airflow velocity and a 20 mA output shall correspond to full-scale airflow velocity. percent. A 4 mA output shall correspond to zero Input impedence for the signal shall be resistive at 250 ohms f 1 d. Airflow dis
22、play. The panel shall incorporate an illuminated digital readout. setting in meter-per-second (mps) on a selectable basis. Airflow velocity displayed shall be mean airflow velocity for the most recent one-second interval. The digital readout shall display airflow velocity or trip point e. Trip-DOint
23、 set. The panel shall enable the setting of a low- airflow alarm trip-point for any value in the selected airflow range. shall detect whenever airflow velocity drops below the trip-point setting for a period of 30 f 5 seconds and shall set a low-airflow alarm state accordingly. The panel shall retai
24、n memory of the trip-point setting at all times, including power loss times. The panel 3 Licensed by Information Handling ServicesA-A-50624 9999974 OLb4823 89T D A-A- 50624 f. Audible alarm. The panel shall incorporate an audible alarm which generates an audio output of from 75 to 95 dB at two feet.
25、 The audible alarm shall sound whenever a low-airflow alarm state is first set and shall remain activated until: i) airflow rate rises above the trip-point setting for at least 10 seconds, or 2) an audible alarm silence switch that shall be incorporated in the panel is manually operated. The audible
26、 alarm silence switch shall be labeled as to function. g. Visual alarm. The panel shall incorporate a visual alarm which flashes on and off when an alarm state is set. until the alarm state is reset to indicate normal airflow. The visual alarm shall be labeled as to function. Alarm flashing shall no
27、t cease h. Test Mode. The panel shall incorporate a manually-initiated test mode which demonstrates/verifies functionality of the visual and audible alarms. i. Airflow velocity output signal. The panel shall output a O Vdc to 10 Vdc analog scalar signal linearly proportional to airflow velocity over
28、 the specified range. The output circuitry shall supply a 10 mA maximum current and shall be “short“ protected. The airflow velocity output signal shall be instan- taneous airflow velocity damped by a one-second time constant. velocity signal shall be available on an accessible screw-lug terminal lo
29、cated inside the airflow panel. The screw-lugs shall be marked as to function. The airflow j. Airflow-loss alarm output signals. The panel shall provide two isolated switch-closure discrete outputs. Closed-contacts shall indicate a low- airflow alarm state or that power has been lost for more than 3
30、0 f 5 seconds. Open-contacts output shall indicate that airflow and power are normal. The switch contacts shall be rated at not less than 1.5 Amps, 115 Vac. The switch-closure output signals shall be made available on an accessible screw-lug terminal located inside the airflow panel. The screw-lugs
31、shall be marked as to function. k. Accuracy. The airflow panel circuitry shall add no more than f 1.75 percent error to the data received from the airflow sensor. The f 1.75 percent maximum allowable error applies to both the digital display of airflow velocity and to the Vdc analog scalar output si
32、gnal which carries airflow velocity information. Panel trip-point detection accuracy shall be within f 3.0 percent of the nominal trip-point setting. 1. Response time. When operating in a standard one-atmosphere environment and an airflow velocity of 25 percent full-scale; the airflow display panel
33、shall achieve a full-accuracy output signal within 1.1 seconds for an airflow velocity signal step increase to 75 percent full-scale. For the same conditions, the airflow velocity display shall achieve a full-accuracy readout of airflow velocity within 2 seconds. m. Repeatability. Repeatability shal
34、l be to within f 1.0 percent of full-scale. 4 Licensed by Information Handling ServicesA-A-50624 W 9999974 0364824 726 = A-A- 50624 n. Sensor fault detect. The panel shall incorporate a sensor fault The panel shall determine whenever the airflow sensor input signal indicator. strays out of the nomin
35、al 2 mA to 20 mA operating range and shall generate a sensor fault alarm accordingly. o. Power. The airflow display panel shall be nominally powered by 115 volt 60 Hz power. An ac input power on/off switch shall be provided. Input ac power shall be fused. p. Power output. The airflow display panel s
36、hall output +15 to +18 Vdc power, 350 mA maximum, for the airflow sensor. q. Interface with airflow sensor. The panel shall connect to the airflow sensor via a three-conductor cable. signal, one conductor the dc power, and one shall be a common conductor, The cable shall be detachable from the panel
37、 sensor via an accessible screw-lug terminal located inside the airflow sensor assembly. The screw-lugs shall be marked as to function. One conductor shall carry the airflow r. Reliability. The airflow display panel minimum mean time between failures (MTBF) shall be no less than 28,000 hours. s. Enc
38、losure. The airflow display panel as mounted in the normal position shall be dripproof. equipment from the vertical (+ 15 degrees) shall cause no harmful operational/ functional effects. Liquid droplets or solid particles falling on the 4. General reauirements. a, Accessibility. All parts and subass
39、emblies which may require servicing, repair, or replacement during the life of the airflow sensing equipment shall be readily accessible. b. Interchangeability. Airflow sensors built in accordance with this CID shall be interchangeable for the specified airflow range. Airflow display panels built in
40、 C. compliance with equipment. d. compliance with shock tolerance e accordance with this CID shall be interchangeable. Vibration. The airflow monitoring system equipments shall be in the vibration tolerance requirements of MIL-STD-167-1 for Type I Shock. The airflow monitoring system equipments shal
41、l be in MIL-S-901 Grade (B), Class I, Light Weight, Type B mechanical standards. Temperature. The airflow monitoring system equipments shall meet the stated accuracy requirements over an operational temperature range of from OC to +5OoC. f. m. The airflow monitoring system equipments shall be in com
42、pliance with the Federal Communications Commission (FCC) Class B Rules for computing devices. 5 Licensed by Information Handling ServicesA-A- 50624 Oualitv assurance provisions. Contractor certification. The contractor shall certify and maintain sub- stantiating evidence that the product offered mee
43、ts the salient characteristics of this Commercial Item Description and that the product conforms to the producers own drawings, specifications, standards and quality assurance practices. The government reserves the right to require proof of such conformance prior to the first delivery and thereafter
44、 as may be otherwise provided for under the provisions of the contract. Regulatorv reauirements. The offerer/contractor is encouraged to use recovered materials in accordance with Public Law 94-580 to the maximum extent practical. Preservation. packaging - packing. - labeling. and marking. Preservat
45、ion, packaging, packing, labeling, and marking shall be as specified. Identification Numbers The following part identification numbering procedure is for government not constitute a requirement for the contractor. purposes P i O08 and doe: X68 - SI P5 Example of part identification number. Probe len
46、gth in cm. Airflow Range (full-scale) in mps. P = airflow panel S = airflow sensor CID number Designate Commercial Item Description Notes. 1. Ordering data. Acquisition documents should specify the following: a. Specify unit type. P = airflow panel and interface cable 6 Licensed by Information Handl
47、ing Services. A-A-5ObZ4 D 9999974 0364826 5T9 A-A-50624 S = airflow sensor and mounting plate b. Specify sensor full-scale (that is, maximum expected) airflow rate value in meters-per-second (mps). O - 1 mps O - 2.5 mps O - 5 mps O - 10 mps O - 25 mps O - 50 mps c. Specify air duct cross-sectional d
48、imensions: 1) for cylindrical duct: diameter in meters or centimeters 2) for rectangular/square duct: length x width in meters or centimeters d. Airflow display panel identification plate labeling. The airflow display panel identification plate shall be labeled “AIRFLOW PANEL“ and shall identify the
49、 applicable CID number, manufacturer name, and part number of the airflow display panel. e. Airflow panel mounting hole pattern. Specify the following hole pattern for naval ship procurements: three 1.55-cm diameter holes configured to form a 30.5 x 25.4 x 25.4 cm isosceles triangle with the longest side in the horizontal plane at the top of the airflow display panel. f. Specify sensor-panel interface cable length in meters. MILITARY INTERESTS: Custodians Army - ME Navy - SH Air Force - 99 Review activities Army - ER Navy - AS Air Force - 13 CIVIL AGENCY COORDINATING ACTIVITIES: COMMERCE -
