(dw) In the design of vaults and pits for
pressure limiting, pressure relieving and pressure regulating equipment, the
installed equipment shall be protected from damage, such as that resulting from
an explosion within the vault or pit, which may cause portions of the roof or
cover to fall into the vault.
Vault or pit openings shall be located so as to minimize the hazards of tools
or other objects falling upon the regulator, piping, or other equipment. The
control piping and the operating parts of the equipment installed shall not be
located under a vault or pit opening where workers can step on them when
entering or leaving the vault or pit, unless such parts are suitably protected.
Whenever a vault or pit opening is to be located above equipment which could be
damaged by a falling cover, a circular cover should be installed or other
suitable precautions taken.
Wis. Admin. Code Public Service
CR Register, October,
1999, No. 526, eff. 11-1-99.