Generally the installation contractor is responsible for use tax on equip/materials/supplies during installation, but can be tax exempt if proper documentation is acquired from the client for tangible personal property - but the exempt claim must be made by the client.
This being a tax-exempt facility, I would think the owner wouldn't want to pay tax on the equipment, but if no claim by the owner, then the contractor does have to collect and pay the use tax.
That said, I am not sure form 891 is the proper form for the sub to use though. Check out forms 3520 and 3372.
------------------------------
Lucrezia Esteban
Controller
East Muskegon Roofing and Sheet Metal Co., Inc.
Certified Building Solutions, LLC
Certified Sheet Metal, LLC
Muskegon MI
(231) 744-2461
------------------------------