28 gauge or .032”
Plastic and aluminum pans are available in the following sizes: 18” / 20” / 22” / 24” / 26” / 28” / 30” and 32”  Make note that these are interior dimensions and the exterior dimensions for each pan size is plus 1”  
The standard depth for the aluminum and plastic pans is 2½”. We also offer 3” deep plastic pans in all sizes for those areas where 3” depth is required. 3” deep pans are only available in 18” / 20” / 22” / 24” / 26” / 28” and 30”
We offer 3 different fitting adaptors for our pans:  #34086 - 1” inside & 1½” over PVC Adaptor. This adaptor allows you to solvent weld a piece of 1” PVC or a piece of 1½”PVC pipe into the adaptor. #34088 – 1” inside & 1½” inside PVC Adaptor. This adaptor allows you to solvent weld a piece of 1” PVC pipe into the adaptor, or solvent weld a 1½” PVC fitting hub onto the adaptor. #34089 - 1” CPVC adaptor. This adaptor allows you to solvent weld a piece of 1”CPVC into the adaptor hub. If you need further clarification on these installation options, please contact customer service and they can send you an illustrated copy of application instructions.
You should always check with your local building and fire officials before installing a plastic pan above a finished ceiling. If the return air to the furnace is not isolated through air tight duct work or the open ceiling is used for the return air, the plastic pan should never be used. If the plastic pan is used in these applications and exposed to flames, the toxic smoke can be drawn back to the furnace and distributed throughout the building.
The plastic pan is not approved for gas water heater installations, and the aluminum pan must be used. The plastic and aluminum pans are approved for electric water heater installations.
3.5 PSI with less than a 1 PSI pressure loss over the time period called out in the tables.  
5 seconds
Concrete pipe is porous and the ASTM guidelines give allowances for this porosity. 
Owner’s Manuals and parts lists on all Cherne equipment can be located in the technical section of the Cherne website. http://www.cherneind.com/Data/ “pieces parts” – replacement parts for the hydrostatic test pumps and joint testers. We do not stock engine parts.