UFC 3-410-04N
25 October 2004
2. Six to eight times the generation velocity to pull particles up
through 20 U.S. standard mesh.
c. Design the air volume for no less than two parts of air to one part of
material to be captured by weight.
d. Design the vacuum hose length less than 7.6 m (25 ft). Locate inlet
valves 9 to 10.7 m (30 to 35 ft) apart when a 7.6-m (25-ft) length of hose is
used. Locate the tool vacuum hose connection on the ends of the
workbench underneath the stands. Size the hose based on the following:
1.
Air volume per hose.
2.
Number of hoses to be used simultaneously.
3.
Transport velocities.
e. Use a multistage centrifugal blower for the vacuum system. Size the
blower according to the following:
1. The total system pressure loss associated with the total number
of hoses to be used simultaneously.
2.
The maximum exhaust flow-rate entering the inlet of the blower.
f. Feed the blower directly into the dirty side of the fabric collector, see
Figure 5-6, used by the industrial exhaust system to minimizes the number
of FRP collection points.
g. Use the manufacturer's data to complete the design because the
LVHV system design data is largely empirical.
5-5
REPLACEMENT AIR. Design replacement air systems to maintain a
pressure (relative to the atmosphere) ranging from -4.97 to -14.9 Pa (-0.02 to -0.06 in wg)
in the shop space and the protective clothing decontamination areas. Maintain the clean
spaces at a positive pressure relative to dirty spaces. See paragraph 2-4.5 for further
details. Provide each ventilated space with a dedicated replacement air system. Conduct
a study of the curing requirements of the resin before specifying temperature and humidity
ranges. Do not re-circulate exhaust air.
5-6
SYSTEM CONTROLS. Design system controls in accordance with
paragraph 2-5 and the following:
a. Position the annunciator panel at the entrance to the dirty space so
operators can monitor operating gauges.
5-8
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