Figure 4. Air duct detector inlet sampling tube:
FLANGE | AIR HOLES | INLET |
| ||
|
| TUBE |
|
| END |
|
| PLUG |
ARROWS | AIR FLOW DIRECTION |
MUST FACE |
|
INTO AIR FLOW |
|
Figure 5. Tube mounting configurations with varying air flow direction:
DOTS INDICATE POSITION OF
SAMPLING TUBE HOLES
AIR FLOW | AIR FLOW | |
DIRECTION | ||
DIRECTION | ||
|
DETECTOR HOUSING 
INLET
TUBE
DETECTOR
HOUSING
A. |
| B. |
EXHAUST | EXHAUST | INLET |
TUBE | TUBE | TUBE |
HORIZONTAL MOUNTING OF HOUSING
EXHAUST |
|
TUBE | DETECTOR |
| |
| HOUSING |
| EXHAUST |
| |
AIR FLOW | TUBE |
| AIR FLOW |
|
| ||
DIRECTION |
|
| DIRECTION |
| INLET | INLET |
|
DETECTOR | TUBE | TUBE | D. |
HOUSING | C. |
| |
VERTICAL MOUNTING OF HOUSING
[5.4.1] Installation For Ducts Less Than 8 Feet Wide
1.If the tube is longer than the width of the air duct, drill a
2.Slide the tube into the centermost housing bushing. Po- sition the tube so that the arrows point into the air flow.
3.Secure the tube flange to the housing bushing with two #6
4.For tubes longer than the width of the air duct, the tube should extend out of the opposite side of the duct. If there are more than 2 holes in the section of the tube extending out of the duct, select a different length using Table 1. Otherwise, trim the end of the tube protruding through the duct so that 1 to 2 inches of the tube extend
outside the duct. Plug this end with the end plug and tape closed any holes in the protruding section of the tube. Be sure to seal the duct when the tube protrudes.
WARNING
In no case should more than 2 air inlet holes be cut off the tube. There must be a minimum of 10 holes in the tube ex- posed to the air stream.
[5.4.2] Installation For Ducts More Than 8 Feet Wide
NOTE: To install inlet tubes in ducts more than 8 feet wide, work must be performed inside the air duct. Sampling of air in ducts wider than 8 feet is accomplished by using the
4 |
