SECTION 2 INSTALLATION

TM 10-6665-297-13&P SECTION 2 INSTALLATION To assure optimum gas monitoring efficiency and trouble-free operation, CD800/830 and CD802/832 Gas Alarm systems should be installed in accordance with the following procedures and specifications, based on engineering design considerations and experience. 2-1 LOCATION OF DETECTORS Detectors should be located at sites where the presence and concentrations of combustible gases must be detected with respect to the following conditions (Figures 2-1 and 2-2): 1. Air currents: Detectors should be located where prevailing air currents contain the fullest possible concentrations of escaping gas. 2. Relative weight of gas: Detectors should be located near the floor for heavier-than-air gases or vapors from flammable liquid spills, and near the ceiling or roof to detect lighter-than-air gases such as hydrogen and natural gas. Vapors from all liquids are heavier than air. 3. Dispersion of gas: Though detectors should not be far removed from any potential source of escaping gas, liquids of low volatility especially demand location of the detector in the immediate vicinity of the escaping vapor, since a slow rate of dispersion could result in falsely low sample readings at short distances from the site. 4. Heat: Standard diffusion type detectors are designed to operate within a range of from -30° to +200°F, but must be located away from areas outside this range. Special high-temperature detectors are available, such as #0050-7005 (for temperatures to 340° F) or High Temperature Probe #0023-7363 with #0023-7338 element, for temperatures to 600° F. Since diffusion sampling is not feasible for detectors located remotely from the area to be monitored, the #0023-4017 remote sample drawing detector assembly is recommended for such applications. Practical sampling line lengths of 75 to 100 feet are possible, using 1/4" OD tubing. CAUTION: The #0023-4017 detector assembly must not be used to draw flammable liquid vapors having flash points higher than the expected ambient temperature from atmospheres at elevated temperatures. On cooling to ambient temperatures, the vapors of such samples may condense in the sample tubing before reaching the reaction chamber. For high flash vapors, Bacharach's special Heated Sample Drawing detector assembly should be used. Consult factory for such applications. 23-9617 7/1/76 2-1