containment rooms

[paulfoster]

Hi, can anybody advise
what is the guidance publication covering containment rooms?
What is the minimum vertical discharge air velocity from roof top mounted fume cupboard extract fans?
regards pf

 

[Whoops]

Is this UK?

I don't think there is a requirement for a discharge velocity, as on fume cupboard discharges. A fume cupborad extract could contain chemical toxins. A Containment laboratory for hazardous organisms woould rely on the HEPA extract filtration to ensure that there are no organisms in the extract airstream.

 

[Whoops]

Sorry about the previous answer, I've misread the question.

Assuming this is the UK then,
"minimum vertical discharge air velocity from roof top mounted fume cupboard extract fans" is covered by BS 7258t.2 :1994. Check this hasn't been superceded. Clause 3.2.4.2. recommends discharge velocities of not normally less than 7 m/s and a design value of 10 m/s is recommended. Higher discharge velocities are sometimes employes, especially in windy locations, but they may cause a noise problem.

If it's not UK I'm sure someone else will help out.

 

[ChasBean1]

The guide most commonly used in U.S. is ACGIH's Industrial Ventilation. ACGIH indicates that for an exhaust duct discharging straight up (fume hood or other), 2,600 feet per minute (fpm) is a good target to keep out rain. Typically 3,000 fpm is recommended. Going much higher can lead to excessive pressure drop at the fan outlet. ACGIH recommends 3,000 fpm to keep a good plume and to discharge contaminants safely above a building's wake.

Whoops' UK standard above is in the same neighborhood, about 1,970 fpm. ACGIH design target is ~15 m/s versus 10 m/s.