Risk Category for Water & Waste Water Treatment Plants 5

[oengineer]

What risk category in ASCE 7 would be appropriate to use for Water & Waste Water Treatment Plants?

My initial thought is to use Risk Category III. However, I am wondering if Risk Category II would be appropriate instead.

Suggestions/comments are appreciated.

 

[MotorCity]

It depends what you are designing. There could be several Risk Categories used at the plant depending how critical the particular building or facility is.

 

[jonev10]

would a WWTP not be an "essential facility"? I'd assume IV

 

[phamENG]

Yeah, if this is a holding tank, an enclosure for switchgear or pumping equipment, or something else that could result in releasing raw sewage if it fails, it's either III or IV (best to consult with the owner/regulator to determine whether or not you exceed the threshold). If it's the office out front, II would likely be appropriate.

 

[oengineer]

It's for a canopy for chemical storage area in a WWTP.

 

[phamENG]

Depends on the chemicals and how they are stored. If the canopy collapses, is it reasonable to assume they'll crack open a tank of sulfuric acid next to a creek leading to a sensitive habitat? Best to classify it as a IV. Is this an aluminum canopy over rigid steel tanks of a relatively weak chemical with robust passive containment in the vicinity that makes it highly unlikely that a leak will cause damage? II might make sense.

Whatever you do, talk to the regulator first. This isn't an office building where any Joe Schmoe can have it built. The municipality or other authority will have an opinion and, likely, a policy.

 

[oengineer]

The chemicals are Sodium Bisulfite & NaOCl

 

[phamENG]

The questions were rhetorical. We're not going to decide for you. You need to investigate and see what kind of impact those can have on the environment, and then determine what you think the RC should be. Then, check with the regulator. Whichever RC is higher, design to that one.

 

[JStephen]

Generally, municipal water tanks are Risk Category IV- they provide fire-fighting water, among other things. That's the default in AWWA D100.

 

[HTURKAK]

I will suggest you to look ICC Clause 1604.5 .

Acc.to TABLE 1604.5 , STP and WTPs are Category III. Copy and paste of relevant item ;

· Power-generating stations, water treatment facilities for potable water, waste water treatment facilities and other public
utility facilities not included in Occupancy Category IV.









I cannot give you the formula for success, but I can give you the formula for failure..It is: Try to please everybody.

 

[JedClampett]

Before you rush into anything, I'd be careful. We design water treatment and wastewater treatment plants typically to III (and by the way, that's pretty much all we do), unless we're in the hazardous chemical storage areas. If you need IV (or just assume it), you're adding a lot of $pecial in$pections and ob$ervation. You're not doing the owner any favors. If the facility provides pressure for firefighting, fine, it's IV. But making water is not the same as providing firefighting pressure. And by the way, wastewater is not considered a hazardous material, at least by code.

 

[oengineer]

I will suggest you to look ICC Clause 1604.5 .

Acc.to TABLE 1604.5 , STP and WTPs are Category III. Copy and paste of relevant item ;

· Power-generating stations, water treatment facilities for potable water, waste water treatment facilities and other public
utility facilities not included in Occupancy Category IV.

Based on this clause, it seems to me like Risk Category III is to be used.

This is what I initially thought.

 

[oengineer]

Thank you all for your comments