9
Setup
The first step for a successful installation is to design a layout of the manifold system. The
following example is intended to demonstrate how to set up a system in a cleanroom facility. On the
facility plan in Figure 1, note the selection of each sample point on the floor plan. While not all
installations will use all the examples, they are appropriate for many users. Each sampling point
should collect through an isokinetic probe, which aids in collecting a sample with a representative
distribution of particle sizes. The manifold system equipment should be located so that the system
complies with Fed Std 209E which states:
“For particles in the 0.1 to 1
µ
m range and for a flow rate
of 0.028m
3
/min (1.0 ft
3
/min) a transit tube of up to 30m may be used. For particles in the range of 2
to 10
µ
m the transit tube should be no longer than 3m Under these conditions, losses of small
particles by diffusion and of large particles by sedimentation and impaction are predicted to be no
more than 5% during transit through the tube. For most applications these tube configurations and
flow conditions will be satisfactory. For special situations, more precise transit particle transit
characteristics can be calculated (see B20.8).”
(Fed-Std-209E, B40.2.1).
Figure 1.
Sampling Points Setup Example
Sampling Point Number
Event/process monitored
Type of isokinetic probe
,
Gowning and cleanup
Through wall
Mid-room point
Direct mount
,
Access points
Through wall
General room activity
Floor mounted vertical
,
,
Workstation activity
Ceiling mounted L-hook
Background baseline
Ceiling mounted J-hook
Table 1. Sampling Points Examples
