Fugitive emission in valves [Second part]

In continuation of the subject, also look into the uploaded files on the subjects by Piet de Later of Dow chemicals.

http://tech.groups.yahoo.com/group/piping_valves/files/

Secondly,  this regulation is to have strict control and leak resistance on the hazardous emission of dust, steam or gas happening due to the external leakages for the safety reasons and long term reliability of the valves.

For instance: Cd, Hg, Ti, CO, NOx  < 0.2 mg/m3.
                   As, Co, Ni, Se             < 1.0 mg/m3.
                   Pb, Sb, F, CN           < 5.0 mg/m3.

For ball valves max. leakage rates of 0.03 g.h-1 are allowed for substances involving a risk potential. The maximum emission rate of He = 4.99x10-2 bars cm3s-1 is deemed to be permissible after a 100,000 operational cycles with Helium test medium at room temperature under a 55 bars pressure. This could be achieved for example, by means of specific design of packing or by means of bellows and a subsequent safety stuffing bushing and with PTFE sealing, if permitted for the service condition.

With regards,
Kannan.