Technical Manual
Page 8
CODEL
OPS.109
Issue : B
Rev. : 1
Date : 23/10/13
Doc. i/d : 0109/6
Ref. : 090028
4.3.1. Fitting of Stub-Pipes and Mounting Flanges
Before proceeding further note that under no circumstances should holes be cut in the stack
with the plant operational if flue gases are under positive pressure with respect to atmosphere.
Even if pressure is believed to be negative great care should be exercised and all appropriate
protective clothing, including eye protection and protective gas mask, should be worn.
The transducer heads should be mounted vertically above each other and no more than 1m apart.
Construct the mounting assemblies by welding each site mounting flange to a suitable stub-pipe, nominal bore
75mm. The pipe should be long enough to keep the equipment clear of any duct lagging and it also helps to
insulate the equipment from high duct temperatures. Suggested stub-pipe mounting arrangements are shown
below for a metal stack and for a concrete stack. In the case of a metal stack it may be necessary to fit stiffening
ribs for added rigidity.
Figure 2 : Stub Pipe Arrangement