Does the criticality of water content change with viscosity? We got an analysis back that had .2% water, and they reported this as above normal, but they had the wrong viscosity oil listed. If the viscosity was changed to a higher viscosity with the same water content, would it be more critical?

I have always heard water in oil limits given as a ppm limit. Sometimes it varies by type of equipment. I have never heard of the limit varying based on the viscosity grade of the oil.

.2% is 2000ppm. Like electricpete said, limits vary by equipment, but more importantly by the type of oil, not the viscosity.

Crankcase oils (automotive) can have that much dissolved water (invisible). Typically hydraulic and R&O oils will have some emulsified water (cloudy) at that level. If it's an EHC oil it may start to degrade quite quickly at .2%

Recently I was given the task of finding a filtration system for a large oil reservoir. It was very interesting to find the amount of information I did about water content in oil and the damage it causes. Some of the information came from the oil and filtration manufacturers then others were end users.
The oil temperature plays a big part in PPM reading. The example I can use, looking at dissolved water, would be if it was a turbine oil, ISO 32, and at a temperature of 140 the permissiable limit was <150 PPM. It is at a point before it starts to turn cloudy. This came from an article by a major oil company. Less is better but it seems that most filtration systems will promote that they can remove down to <100 to <150 PPM as I found out by reading many specfications and lubrication articles.
Charts are available on the web that will show oil life extension of 5X by reducing your water in the oil from 2500 PPM to 156 PPM.

This message has been edited. Last edited by: Don Jones,

You might be interested to download Oil Analysis Table I prepared on my articles portion
http://www.rsareliability.com/articles.htm

100 - 300 ppm - Alert
300 - 800 ppm - Danger
800ppm and above - extremely danger

By the way, we are just speaking of water, should metals be present it will act as a catalyst to accelerate oil's oxidation which therefore will have an effect on its viscosity.

Note that standard sample use is per 100 ml of oil.

My Warm Regards,