A. The cost of equipment chargeable to the gas plant accounts, unless otherwise indicated in the text of an equipment account, includes the net purchase price thereof, sales taxes, investigation and inspection expenses necessary to such purchase, expenses of transportation when borne by the utility, labor employed, materials and supplies consumed, and expenses incurred by the utility in unloading and placing the equipment in readiness to operate.B. Exclude from equipment accounts hand and other portable tools which are likely to be lost or stolen or which have relatively small value (for example, $50 or less) or short life, unless the correctness of the accounting therefor as gas plant is verified by current inventories. Special tools acquired and included in the purchase price of equipment shall be included in the appropriate plant account. Portable drills and similar tool equipment when used in connection with the operation and maintenance of a particular plant or department, such as production, transmission, distribution, etc., or in "stores," shall be charged to the plant account appropriate for their use.C. The equipment accounts shall include angle irons and similar items which are installed at the base of an item of equipment, but piers and foundations which are designed to be as permanent as the buildings which house the equipment, or which are constructed as a part of the building and which cannot be removed without cutting into the walls, ceilings or floors or without in some way impairing the building, shall be included in the building accounts.D. The equipment accounts shall include the necessary costs of testing or running a plant or part thereof during an experimental or test period prior to becoming available for service. The utility shall furnish the Department, upon request, with full particulars of and justification for any test or experimental run extending beyond a period of 30 days.E. The cost of efficiency or other tests made subsequent to the date equipment becomes available for service shall be charged to the appropriate expense accounts, except that tests to determine whether equipment meets the specifications and requirements as to efficiency, performance, etc., guaranteed by manufacturers made after operations have commenced and within the period specified in the agreement or contract of purchase, may be charged to the appropriate gas plant account.