maintenance staff vs service staff

maintenance staff and service staff both are nouns.

Word	Noun	Adjective	Verb	Adverb
maintenance staff	Yes	No	No	No
service staff	Yes	No	No	No

As nouns, maintenance staff and service staff are synonyms defined as:

maintenance staff and service staff: those in a business responsible for maintaining the physical plant

maintenance staff (noun)	service staff (noun)
those in a business responsible for maintaining the physical plant	those in a business responsible for maintaining the physical plant