QUV test exposure related to actual exposure in field.

[SAK123]

I am involved in using fabric materials for making large structures. Fabric tensile strength after UV exposure is required to determine the amount of material property degradation as a function of UV exposure. At present we just set some samples on a QUV machine for a few thousand hours and then conduct tensile testing (all per ASTM). Depending on the material after a such a test, the post UV exposure tensile strength can range from 87% to 100% of the original control sample.

A customer of mine has a particular application in GUAM - where there is high UV exposure.

My question is there any equation relationship between the time the sample spends in UV testing exposure in the QUV machine and the amount of time in the field under direct sun exposure ? What I am looking for is some equation that relates the known or estimated sun exposure for a specific location on the globe to the number of hours in the testing machine to reproduce the same UV exposure. For example, a building with a life of 20 years located in Florida would need XXX hours in the QUV machine under exposure A.

Thanks for any input.

Regards.

 

[IRstuff]

Wouldn't your equipment supplier know this?

TTFN

FAQ731-376

 

[Demon3]

I've used a machine in the past where that was written on the side of the machine. x many hours = y many month in Florida or z many months in Northern Europe. I am pretty sure you could dig up some guidelines with web search.

Just remember that no accelerated aging testing is accurate. It may enable you to rank materials but any estimates of real-world weatherability are likely to be way off.


Chris DeArmitt

 

[patprimmer]

Even ranking can be a bit off as the UV spectrum of the test is constant whereas natural light varies as does everything else in the natural environment with any thing from temperature, latitude, humidity, cloud cover, ozone layer, dust, and pollution are what come immediately to mind.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers for professional engineers

 

[IRstuff]

You should look at the test methods cited by your manufacturer.

TTFN

FAQ731-376