English to Spanish Tech/Engineering Construction / Civil Engineering material and/or equipment escalation (in a contract)

This phrase shows up in a cotract I'm currently translating into spanish. the whole paragraph goes like this:


"The Subcontract is not subject to Price Adjustments for wage, material and/or equipment escalation without a written subcontract modification."

I can't seem to find the right translation for "material and/or equipment escalation" though. Any input would be most welcome.

Thanks eveybody!