water quality for hydro testing 1

The generic description is "potable water". I.e. if you're prepared to drink it then it's ok.

Please provide some sort of context and what you have. This is not 20 questions here.....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

So, to see WHY his question is VERY important, or WHY water quality is meaningless, look at three examples.

Oil piping in a refinery or truck transfer station. The water will be drained after the hydro, the pipe will not corrode during the hydro - pipe cleanliness or flushing and water draining is simplified if the water is "clean" potable water, right? After operation for a while, you don't want (can't!) drain the hydro water of a dirty ily system to the river or sewage, but in construction, disposal of potable water and its price are low.

Food process or medicine research or LOX. Cleaning is essential, final flushing has to done with ultra pure DI water. Very expensive process, very costly if done wrong. Initial hydrostatic testing (after rough flushing) sometimes is cheaper with pure water so you don't contaminate the new pipes with potable Cl-filled water.

Same for nuke plants. Getting rid of the potable water chemical residue is more expensive than buying enough pure water to flush and then leave full for the hydrostatic test. So we used chemically pure water for flushing, hydro's and static filling.

A- The pH number and what happens if it is above or below the requirement?

Potable water pH is generally between 6-9 pH units. Low pH water is corrosive to carbon steel. High pH water may cause scale to develop from the dissolved calcium and magnesium normally present in potable water.

B-Chloride number and explain?

Corrosion is a complicated subject, but chloride concentrations above 200 mg/L would typically be considered to be corrosive.

C- what happens for the water to become turbidity and what the accept it result and why?

Turbidity consists of particulates in water. Potable water should have not particulates. Raw water such as from a river would have turbidiy. If you hydrotest with turbid water, it will be difficult to flush the particulates completely out of the piping.

D- frequent water change and explain?

As long as the water is potable, frequent water changes should not have much effect on the hydrotest.

One thing that is missing from the question and answers is disposal of water. New pipe (that is not food-grade or nuclear grade) has some amount of mill scale, corrosion products, oils, etc. on the inside of the pipe. Water that is introduced for a hydrotest will react with these contaminants and any pipeline subject to DOT jurisdiction must treat used hydrotest water as hazardous waste (you can't just let it run out into the bar ditch any more). I understand that the OP is not in the U.S. or subject to DOT, but his profile says he's in Saudi Arabia and their pipeline regulations have many similarities with DOT regulations.

I brought this up because of the OP's question "D". Adding water is not a physical problem (may impact your test acceptance criteria), but removing water is a big deal, letting even small amounts out onto the ground can be in violation of the law.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

disposal of hydrotest water generally requires a "de-minimus" NPDES permit.

for instance:

The document ASME PCC-2 provides soms guidance on this subject ; I have seen a maximum of 50 ppm repeatedly for stainless steels

MJCronin
Sr. Process Engineer

Dont forget to inhibit corrosion from hydrotest water with some biocide and oxygen scavenger.

I am in Middle East (Qatar) and we have maximum 10 ppm chloride ion content for SS and 50 ppm for all others.

Thank you everyone that helped a lot.