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. Author manuscript; available in PMC: 2015 Dec 15.
Published in final edited form as: Hum Factors. 2012 Jun;54(3):334–345. doi: 10.1177/0018720812445805

Figure 2.

Figure 2

The two anthropometric methods for ladder positioning and their schematic geometrical representation. (A) ANSI A14 method. (B) Fireman method. (C) ANSI A14 method scheme. (D) Fireman method scheme. θANSI = 90° − α1 + α2 = 90° − arcos[(d2 + e2 − b2)/(2*d*e)] + arctan(c/a), and θFireman = 90° − arctan[(b − c)/a)], where a = shoulder (acromial) height in standing (with shoes), b = grip reach from shoulder (reduced by half of the ladder rail width), c = ankle-to-toe length (average of medial and lateral measurements with shoes), d = length from ladder bottom to fifth rung, and e = (a2 + c2)0.5.