Hospital entrance sign.

By Steven Dannaway, PE, DBIA – If you are involved in the design of acute care facilities, you generally know which non-structural equipment requires seismic anchorage design. But can you easily identify what equipment is exempt from this requirement?

Anyone designing acute care facilities knows seismic anchorage and bracing all non-structural equipment and distribution systems is a significant task. To lessen this burden, it is useful to understand what equipment does not require engineering calculations or an engineer’s input. This is often referred to as “exempt equipment.”

Exempt Roof and Floor Mounted Equipment:
CBC 1617A.1.18 ASCE 7, Section
Any equipment weighing 400 lbs or less, and that has a center of gravity less than 4 ft high, is exempt equipment. You need to show the anchorage on the plans, but it only needs to indicate a “positive attachment.” Positive attachment does not mean equipment can simply rest on the floor, roof, or support. However, if your detail is showing screws, lags, expansion bolts, etc. positively attaching the equipment to the floor or roof, no further proof or calculations should be required.

Exempt Moveable or Mobile Equipment:
CBC 1617A.1.18 ASCE 7, Section (and d)
Moveable and mobile equipment, especially larger heavier moveable and mobile equipment, requires detachable restraints “in a manner approved by the enforcement agency.” You will need to detail the restraints on the plans, such as brackets with a detachable chain around the equipment, but it can be a practical agreeable solution. The code does not technically require you to provide supporting engineering calculations showing compliance for code forces. However, there are times when OSHPD may request such engineering calculations despite this.

Exempt Wall Mounted Equipment:
CBC 1617A.1.18 ASCE 7, Section
Only wall mounted equipment (or any component) less than or equal to 20 lbs is considered exempt. This exemption came to be after a code change removed an exemption for wall mounted equipment weighing 150 lbs or less and with a center of gravity not more than 12 in from the wall surface. However, sheet ST2.04 of OPD-0001-13 shows a piece of wall mounted equipment attached to backing per ST5.00 with #10 SMS screws at 12 in o.c. putting a load of 50 lbs on each stud as preapproved. This change left the exact code limit for exempt wall mounted equipment unclear in our experience. Often OSHPD will not request structural calculations showing code compliance for attachment of wall mounted equipment (especially electrical panels) that are roughly 150 lbs or less and are being attached by expansion bolts to a concrete or masonry wall or attached by (4) #12 SMS to typical backing per ST5.00 of OPD-0001-13. We recommended that you detail that first, and wait for a request of structural calculations.

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