RECORDING LOANS : All loans of stock, both apparatus and books, should be recorded in writing, no matter what time-scale is involved. In the case of apparatus and equipment, you need to know the name of the person concerned, what he/she is borrowing (and possibly why), where he/she is going to use it and when you can expect it to be returned. Items that feature in the official inventory should not be removed from the premises unless written permission has been given. In this situation, you could record this written permission with the loan details.
"Borrowing" stock is not the same as using stock that you provide for experimental work.
In an educational establishment, it is necessary to record loans of textbooks to students. This is made easier if sets of books are numbered so that individual books can be identified. If an exercise book is ruled appropriately, it makes a useful loan record.