Fingers developed after years? Or at the time of install?

[Bham]

32 minutes ago, Roach said:

 

Just thinking... I wonder how the UV rejection is doing at this point... becuase 1st.... its a 50% film.... 2nd that it's 23 yrs old. 

 

sans the couple panes I replaced.

 

 

 

That is one question I have always had also.  I think there is some type of expensive meter that determines performance (TSER) of films and I've always wondered how much the performance degrades like the shading does.  

[Tintguy1980]

23 hours ago, Roach said:

 

Just thinking... I wonder how the UV rejection is doing at this point... because 1st.... its a 50% film.... 

 

UV degradation will vary depending on product construction: UV treated poly layers, UV protection in laminating adhesive, UV protection in mounting adhesive, and importantly, the quality of the UV protective product used. Only the top tier manufacturers are known to have UV protection through out the construction.

 

Testing would require a sample of the original film from the date of installation (same lot number sample likely not available after 2 decades +) and comparatively measuring the pristine sample against the crud film while on the glass with same day/time sunlight shining through.

 

A couple of measuring devices below:

 

This meter example is likely more accurate than the second link.

https://sperdirect.com/products/uv-light-meter-uva-uvb?currency=USD&variant=35844887183517&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&gclid=EAIaIQobChMIwO6w3MPw9gIVUPzjBx3nwAMWEAQYASABEgJKjvD_BwE

 

This one is obviously inexpensive, but may suffice for degradation measurements.

https://www.walmart.com/ip/Walmeck-Portable-Digital-Ultraviolet-Radiation-Detector-Ultraviolet-UVI-Meter-Radiometer-Tester-Protective-Equipment-Testing/967112395?wmlspartner=wlpa&selectedSellerId=101043425&&adid=22222222227479831776&wl0=&wl1=g&wl2=c&wl3=563186498573&wl4=pla-1465957310631&wl5=9008686&wl6=&wl7=&wl8=&wl9=pla&wl10=278534602&wl11=online&wl12=967112395&veh=sem&gclid=EAIaIQobChMIwO6w3MPw9gIVUPzjBx3nwAMWEAQYCCABEgKybfD_BwE&gclsrc=aw.ds

 

 

My guess would be <50% protection after 23 years and would certainly be shocked to fin it was greater than 50%