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1.36D

MISCELLANEOUS METALWORK (Continued)

D. Standard designs of spiral stairways are shown on the following drawings:

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E. A ladder is used where it is necessary to ascend or descend at an angle
with the horizontal exceeding 50 degrees. Ship ladders are used where the
slope is between 50 and 75 degrees. No attempt has been made to prepare
standard drawings covering this type of ladder; however, Drawing No.
103-D-6 should be used to establish principal dimensions. Ladders with
slopes greater than 75 degrees may consist of rungs embedded in the
concrete structure at 12-inch centers, or a fabricated steel ladder bolted
to the structure. Ladders frequently extend for considerable distances;
therefore, from a safety standpoint the following standards should be
adhered to where possible:

(1) Maximum length for single ladder, 30 feet.

(2) Minimum clear width from center line of ladder to either side, 15 inches.

(3) Clearances as indicated on Drawing No. 103-D-6.

(4) Ladders greater than 25 feet long should be equipped with a cage or basket; however, where these ladders are used infrequently, the question of installing cages should be determined on the basis of individual requirements.

F. Designs of ladders are indicated on the following drawings:

Ladders

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Drawings

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