Observation Windows – FAQs


How are observation windows used?

Most customers install two observation windows; one to look through and one to shine a light into. Sometimes they are placed on opposite sides of the container so it is easy to see light coming in from the opposite side. If you can see the light, it means the container does not have a load in it.

What does the thread callout (3/4-14 straight pipe IAW PPP-P-420, Class D) mean? Do I need a 3/4” hole in my container to mount this device (TA356, TA350, TA354 and their derivatives)?

This thread is misleading because it actually has a maximum major diameter of 1.027”. It is commonly used on the small bung of a 55 gallon drum. The reason our humidity indicators have this thread is that they were initially used most commonly on 55 gallon drums.

Can I get a custom observation window?

Yes. AGM’s Engineering Department has designed hundreds of modified and custom versions for previous customers.

Do these observation windows meet any specifications?

At this time, there are no applicable observation window specifications. However, most of these devices would meet the requirements of SAE AS26860, which governs humidity indication, except for the parts pertaining to the humidity indicating cards.

I need a glass window, a special finish and fluorosilicone gaskets. Can I get that?

Yes. We commonly supply special features such as these for many of our customers.