Learn Russian: При необходимости мы разрешаем использование этого оборудования. - If necessary, we permit the use of this equipment.

While при often shows physical proximity, using при with the prepositional case of an abstract noun expresses a condition or prerequisite. Phrases like при необходимости (in case of necessity) or при желании (if desired) act like "if" clauses in English.

Could I just use an "if" clause here, like если необходимо?

Yes, если необходимо or если нужно works perfectly and is more common in everyday speech. При необходимости sounds a bit more professional, official, or formal, which fits well with a sentence about permitting the use of equipment.

Why use the noun использование instead of the verb использовать?

The verb разрешать (to permit) can take either an infinitive (we allow them to use) or a direct object noun in the accusative case (we permit the use). Both are grammatically correct, but using the verbal noun использование sounds slightly more formal and matches the official tone of the sentence.

Why is этого оборудования in the genitive case?

It acts like the English word "of" to connect two nouns. Since it tells us what the использование (use) applies to, это оборудование changes to the genitive case этого оборудования (of this equipment).