Emerson Rosemount 700XA Reference Manual page 54

Installation and start-up
June 2022
WARNING
Failure to observe precautionary signs may result in serious injury or death to personnel.
Observe all precautionary signs posted on the certified explosion-proof equipment.
Consult your company's polices and procedures and other applicable documents to
determine wiring and installation practices that are appropriate for hazardous areas.
4.3.4 Sample system requirements
Line length
Sample line tubing material
Dryers and filters
Pressure regulators and
flow controllers
Pipe threads and dressings
Valving
54
If possible, avoid long sample lines. In long flow sample lines, velocity
can be increased by decreasing downstream pressure and using
bypass flow via a fast loop.
NOTICE
Stream switching requires a sample pressure of 20 psig (1.38 barg).
• Use sulfur-inert tubing for H
use stainless steel tubing.
• Ensure tubing is clean and free of grease.
Use small sizes to minimize time lag and prevent back diffusion.
• Install a minimum of one filter to remove solid particles. Most
applications require fine-element filters upstream of the gas
chromatograph (GC). The GC includes a 2-micron filter.
• Use ceramic or porous metallic type filters. Do not use cork or felt
filters.
NOTICE
Install the probe/regulator first, immediately followed by the
coalescing filter and then the membrane filter.
• Use stainless steel wetted materials.
• Parts should be rated for sample pressure and temperature.
Use PTFE tape. Do not use pipe thread compounds or pipe dope.
• Install a block valve downstream of sample takeoff point for
maintenance and shutdown.
• The block valve should be a needle valve or cock valve type, of
proper material and packing, and rated for process line pressure.
Reference Manual
2-3-9000-744
S streams; for all other applications,
2
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