fundamentals of engineering supplied-reference handbook - Ventech!

ERGONOMICS
NIOSH Formula
Recommended Weight Limit (U.S. Customary Units)
= 51(10/H)(1 – 0.0075|V – 30|)(0.82 + 1.8/D)(1 – 0.0032A)
where
H = horizontal distance of the hand from the midpoint
of the line joining the inner ankle bones to a point
projected on the floor directly below the load
center,
V = vertical distance of the hands from the floor,
D = vertical travel distance of the hands between the
origin and destination of the lift, and
A = asymmetric angle, in degrees.
The NIOSH formula as stated here assumes that (1) lifting
frequency is no greater than one lift every 5 minutes; (2) the
person can get a good grip on the object being lifted.
Biomechanics of the Human Body
Basic Equations
Hx + Fx = 0
Hy + Fy = 0
Hz + Fz = 0
THxz + TFxz = 0
THyz + TFyz = 0
THxy + TFxy = 0
The coefficient of friction µ and the angle α at which the
floor is inclined determine the equations at the foot.
Fx = µFz
With the slope angle α
Fx = µFzcos α
Of course, when motion must be considered, dynamic
conditions come into play according to Newton's Second
Law. Force transmitted with the hands is counteracted at the
foot. Further, the body must also react with internal forces at
all points between the hand and the foot.
194
INDUSTRIAL ENGINEERING (continued)
PERMISSIBLE NOISE EXPOSURES *
Duration per day, hours Sound level, dBA
8 90
6 92
4 95
3 97
2 100
1 1/2 102
1 105
1/2 110
1/4 or less 115
* Exposure to impulsive or impact noise should not exceed
140 dB peak sound pressure level.
FACILITY PLANNING
Equipment Requirements
Pij = desired production rate for product i on machine j,
measured in pieces per production period,
Tij = production time for product i on machine j,
measured in hours per piece,
Cij = number of hours in the production period available
for the production of product i on machine j,
Mj = number of machines of type j required per
production period, and
n = number of products.
Therefore, Mj can be expressed as
n PijTij
M j = ∑
= 1
C
i ij