ACI 350-06 Environmental Exposure, Normal vs. Severe

[ronjon322]

ACI 350 provides criteria for Normal and Sever Environmental Exposure. I see the requirements for Normal exposure stated in Sections 2.1 and 10.6.4.5 to be liquids with a pH greater than 5, or exposure to sulfate solutions of 1000 ppm or less and Severe being anything exceeding Normal.

Does anyone have documentation stating the typical environmental conditions of municipal/domestic wastewater treatment plants? Typical pH levels and typical sulfate ppm levels.

Several references online state that basic rain/stormwater has pH 5.5 or greater and domestic wastewater is typically pH 6-8 or greater. References also state sulfate concentration much lower than 1000 ppm. So based on this using Normal Environmental Exposure should be sufficient. Can someone prove otherwise?

Thanks

Measure twice, cut once.

 

[JedClampett]

Whoa there Bucky. Raw sewage releases hydrogen sulfide, which through some biological processes, creates sulfuric acid. That's your issue. The criteria for severe exposure should be followed, plus any concrete exposed to sewer gasses needs to be coated. The requirements for severe exposure are not that hard to accomplish (off the top of my head; fly ash, w/c=.4, 4500 psi concrete) so why take a chance?
Why I appreciate new blood, there's companies who exclusively design sewage treatment facilities, and we have developed specifications and procedures that we follow religiously. You need to ask someone with that background for this kind of question. Or ten years from now, I'll be visiting the plant.

 

[ronjon322]

Thanks Jed. Very helpful to hear advice from others.
My question was really pertaining to the reinforcing requirements of ACI 350-06, 10.6.4.1. While using the severe exposure criteria gives that warm fuzzy feeling that helps one sleep at night my concern was mainly just about over designing.


Measure twice, cut once.