Otdfbt

I'm revising procedural documentation and checklists for my work. One of the checklist questions are written as "Is the equipment in the work center calibrated, and operating within specified parameters?"

I feel like it should be written as "Are the equipment in the work center calibrated and operating within specified parameters?"

But in this case, the term "equipment" can refer to one piece of equipment or multiple pieces of equipment. The latter is most often the case in this context. I know it seems kinda silly, but it's still driving me crazy.

Generally a noncount noun is treated as singular for the purposes of subject-verb agreement even when it may refer to multiple items. From Everyday Grammar:

Grammatically, a noncount noun is always singular, even if it refers to multiple items like furniture, luggage, or equipment.

Semantically, readers will understand that the equipment refers to, say, the table saw and the drill, or any equipment in the room. Similarly, if I ask, "Is the clothing in the laundry?" I am looking for anything that is categorically clothing, whether that's a single item or all the clothes I've worn this week. (Compare with a count noun, where the number of items matters: "Is the shirt in the laundry?" "Are the shirts in the laundry?")

So you should keep the verb in the checklist question in the singular.

"Equipment" is an uncountable noun, and is therefore always treated as a singular.

For example, you couldn't say

*"I have two equipments",

instead you would have to use

"I have two pieces of equipment."

Because equipment is treated as a singular noun, even when it refers to multiple objects, it must take the singular form of the verb, so

"Is the equipment in the work centre calibrated?"

would be correct.

This is the case for most nouns that refer to collections of things. However, when talking about countable nouns, where the number is unknown, you typically use the plural form. For example, imagine you are visiting a friend who loves dogs, and you assume they have at least one dog at home. You might ask:

"Are there dogs at your house?"

Here, you use the plural form, because you don't know whether there are 0, 1 or many dogs.

And further to what has already been said in the other answers, if you really, really want to use plural you could say:

Are all the pieces of equipment in the work centre calibrated...

But this can come across as clumsy.