Safety Requirements for Batteries and Battery Rooms

Article 320 of NFPA 70E provides safety requirements for working on and around storage batteries. As with other Articles in this standard, it takes a concept approach rather than a highly detailed, prescriptive approach. This fact becomes clear at the outset, when you read the Informational Note under the Scope [320.1]. It lists not just two or three other standards, but eleven.

These other standards provide "additional information on best practices for working with exposed stationary batteries that exceed 50V, nominal." Six of these are IEEE standards, two are NFPA standards, and two are OSHA standards. There's one from DHHS (NIOSH).

What's in a word?

Section 320.2 defines 10 terms. For people regularly engaged in battery work, these terms and their "battery lingo" definitions are familiar. Yet many words commonly used in battery work are not listed here (e.g., string and float charge). You will encounter a much larger "battery lingo" vocabulary when reading through the 11 standards mentioned earlier.

Assessment

NFPA 70E makes risk assessment a core safety practice. For battery work, the risk assessment must address three types of hazard [320.3(A)]:

Chemical

Electric shock

Arc flash

You must also assess the risks associated with the types of tasks to be performed. The task of cleaning battery terminals presents different risks than the task of measuring the float voltage on a string.

The room

Each battery room or enclosure must be accessible to only authorized personnel [320.3(A)(2)(c)]. Does this mean a sign or a lock? Art. 320 doesn't say, so consider these things.

Locks almost certainly ensure there won't be unauthorized access. However, locks cost money and can cause delays when quick access is critical. If conditions are such at the facility that a sign will do the job, a sign may be sufficient.

For example, in a limited access facility, such as a manufacturing plant or power generating plant, a physical lock can also be used, but a sign may be all that's needed if all employees are properly trained.

At one...