926                              Laws of Maryland                       Ch. 405

(a)    Finishing and assembling buildings, pressing buildings, and
mixing buildings constructed, improved, or to which additions are
made after July 1, 1970, shall have exterior walls and roofs con-
structed of non-combustible material and be of frangible or "break-
way" construction.

(b)    No building shall have a basement or be more than one
story high. Interior wall surfaces and ceilings of buildings shall
be smooth, free from cracks and crevices, fire resistive, and with
a minimum of horizontal ledges upon which dust may accumulate.
Wall joints and openings for wiring and plumbing shall be sealed to
prevent entry of dust. Floors and work surfaces shall not have
cracks or crevices in which explosives may lodge. Mixing and press-
ing buildings shall have conductive flooring, properly grounded, and
conductive footwear shall be worn by operating personnel and
visitors.

(c)    All buildings shall have conspicuously posted signs indicating
the maximum number of workers and transients permitted therein
at any one time.

(d)    Small buildings, in which the designated capacity is one
person, may have only one exit. All other buildings shall have at
least two exits for each operating room or building. Each exit shall
be at least 30 inches wide and located at opposite ends of the area
involved. Exits shall be located so that the path of travel from the
work place is unobstructed. Exit doors shall open outward, shall not
be locked during hours of occupancy, and shall not be obstructed.

(e)    No stoves, exposed flame, or electric heaters may be used in
any part of a fireworks plant except in a boiler room, machine shop,
office building, pumphouse, or lavatory in which the presence of fire-
works, fireworks components, or volatile chemicals is prohibited.
Heating shall be by means of steam, indirect hot air radiation, hot
water, or any other means approved by the State Fire Prevention
Commission. Unit heaters located inside buildings which at any time
contain explosive composition shall be equipped with explosion-proof
motors, and switches controlling the motors shall be located outside
the building.

(f)     Where artificial lighting is required, it shall be by electricity
with vapor-proof keyless lamps. Temporary or loose electric wiring
or extension lights are prohibited, except during repair operations
while using approved type temporary extensions and only after the
area has been cleared of all explosive composition and washed down
of dust. All wiring shall be of permanent character installed in
approved conduit. All electrical service shall be in accordance with
applicable electrical codes. No open knife switches shall be used in-
side buildings, except in warehouses.

(g)    In any building which at any time contains explosive com-
position, all electric motors, fans, open switches or other devices
capable of producing an open spark shall be located on the outside
of the building in such manner that no open spark can be introduced
into the building. All presses and other mechanical devices shall be
properly grounded to prevent the accumulation of static electricity.

(h) A master switch shall be provided at the point where elec-
tric current enters the plant, which will, upon being opened, im-
mediately cut off all electric current to the plant.