3003 W CASINO RD BLDG 40-92 2024-06-12

[6]SAMPLING TUBE INSTALLATION ing out of the duct,select a shorter tube using Table 1. Otherwise,trim [6.1]SAMPLING TUBE SELECTION the tube to leave approximately 1 to 2 inches extending outside the duct. The sampling tube must be purchased separately. Order the correct length, Plug the end with the end cap and tape closed any holes in the protrud- as specified in Table 1, for width of the duct where it will be installed. It is ing section of tube.Be sure to seal the duct where the tube protrudes. recommended that the sampling tube length extend at least 2/3 across the duct FIGURE 4. width for optimal performance. TABLE 1.SAMPLING TUBES RECOMMENDED FOR DIFFERENT 12- DUCT WIDTHS: Outside Duct Width Sampling Tube Recommended* Up to 1 ft. DST1 2- 1 to 2 ft. DST1.5 2 to 4 ft. DST3 /4 DETECTOR 4 to 8 ft. DST5 HOLE 8 to 12 ft. DST10(2-piece) H0215-00 NOTE:Air currents inside the duct may cause excessive vibration,especially *Must extend a minimum of 2/3 the duct width. These sampling tubes can when the longer sampling tubes are used.In these cases,a 3 inch floor flange only be used with new InnovairFlex duct smoke detectors. (available at most plumbing supply stores) may be used to fasten the sam- The sampling tube is always installed with the air inlet holes facing into the pling tube to the other side of the duct. When using the flange/connector air flow.To assist proper installation,the tube's connector is marked with an mounting technique,drill a 1 to 1'/4 inch hole where the flange will be used. arrow.Make sure the sampling tube is mounted so that the arrow points into [6,3]MODIFICATIONS OF SAMPLING TUBES the airflow as shown in Figure 3.Mounting the detector housing in a vertical There may be applications where duct widths are not what is specified for the orientation is acceptable provided that the air flows directly into the sampling installation.In such cases,it is permissible to modify a sampling tube that is tube holes as indicated in Figure 3. The sampling tube and exhaust tube longer than necessary to span the duct width. can be mounted in either housing connection as long as the exhaust tube is mounted downstream from the sampling tube. Use a 0.193 inch diameter(u10)drill and add the appropriate number of holes so that the total number of holes exposed to the air flow in the duct is 10 to 12. FIGURE 3.AIR DUCT DETECTOR SAMPLING TUBE: Space the additional holes as evenly as possible over the length of the tube. SAMPLING TUBE ENDCAP NOTE:This procedure should only be used as a temporary fix and is not in- tended as a substitute for ordering the correct length tubes. ® ® ® [6.4]REMOTE SAMPLING TUBE INSTALLATION ® The detector arrangement can also incorporate remote mounting of the sam- pling tube and/or exhaust tube.In this case both the detector,sampling tube ® and exhaust tube (if included) should be rigidly mounted to withstand the pressure and vibrations caused by the air velocity.The location of the detec- ARROW MUST FACE AIR FLOW tor's sampling tube should be such that there is uniform airflow in the cross INTO AIR FLOW DIRECTION section area. H0551-00 The pressure differential across the sampling and exhaust ports in the detector CAUTION: The sampling tube end cap, included with the detector, is criti- housing shall be verified to be between 0.01 and 1.11 inches of water. Do so cal to proper operation of the duct smoke detector.The end cap is needed to by measuring the pressure difference between the inlet and outlet ports on the create the proper air flow to the sensor of the duct smoke detector.Once any detector housing using a manometer as described in Section 7.1. sampling tube length adjustments are made,plug the end of the sampling tube [7]MEASUREMENT TESTS with the provided end cap. [7.1]AIR FLOW A plastic exhaust tube is included with the unit to be installed if needed.In- The D4120 is designed to operate over an extended air speed range of 100 to stall into the housing connection that is downstream from the sampling tube 4000 FPM.To verify sufficient sampling of ducted air,turn the air handler on connection. The exhaust tube can be installed from the front or back of the and use a manometer to measure the differential pressure between the two detector.A longer 1 foot exhaust tube,model ETX,is available as an accessory sampling tubes.The differential pressure should measure at least 0.01 inches in cases where the molded exhaust tube does not extend at least 2 inches into of water and no more than 1.11 inches of water. Because most commercially the duct. available manometers cannot accurately measure very low pressure differen- [6.2]SAMPLING TUBE INSTALLATION tials,applications with less than 500 FPM of air speed may require one of the 1. For tubes shorter than the width of the duct, slide the sampling tube, following: 1)the use of a current-sourcing pressure transmitter(Dwyer Series with installed end cap,into the housing connection that meets the air- 607)per Section 7.2,or 2)the use of aerosol smoke per section 12.5.3. flow first.Position the tube so the arrow points into the airflow as shown [7.2]LOW FLOW AIR FLOW TEST USING DWYER SERIES 607 in Figure 3. Per NFPA sampling tubes over 3 feet long should be sup- DIFFERENTIAL PRESSURE TRANSMITTER ported at the end opposite the duct detector.In ducts wider than 8 feet, Verify the air speed of the duct using an anemometer. Air speed must be at work must be performed inside the duct to couple the other section of least 100 FPM.Wire the Dwyer transmitter as shown in Figure 5.Connect the the sampling tube to the section already installed using the'/2 inch con- leads of the meter to either side of the 1000Q resistor.Allow unit to warm up duit fitting. Make sure that the holes on both sections of the air inlet for 15 seconds.With both HIGH and LOW pressure ports open to ambient air, sampling tube are lined up and facing into the airflow. measure and record the voltage drop across the 100052 resistor(measurement 2. For tubes longer than the width of the duct,the tube should extend out 1),4.00 volts is typical.Using flexible tubing and rubber stoppers,connect the of the opposite side of the duct.Drill a 3/4 inch hole in the duct opposite HIGH side of the transmitter to the sampling tube of the duct smoke detec- the hole already cut for the sampling tube.Ensure that the sampling tube for housing, and the LOW side of the transmitter to the exhaust tube of the is angled downward from the duct smoke detector to allow for moisture duct smoke detector housing.Measure and record the voltage drop across the drainage away from the detector. The sampling tube should be angled 100052 resistor (measurement 2). Subtract the voltage recorded in measure- at least 1/4"downward for every 12"of duct width per Figure 4.There ment 1 from the voltage recorded in measurement 2.If the difference is greater should be 10 to 12 holes spaced as evenly as possible across the width of than 0.15 volts,there is enough air flow through the duct smoke detector for the duct.If there are more than 2 holes in the section of the tube extend- proper operation. 3 156-2967-008R 06-10