2.4.8 Top of Counterweight Clearances

The top of counterweight clearance shall be not less than the sum of the following items:

(a) the bottom car runby (see 2.4.2)

(b) the stroke of the car buffer used, or the remaining stroke when the buffer is compressed with the car at the bottom terminal landing (see 2.4.2 and 2.22.4.8)

(c) 150 mm (6 in.)

(d) one-half of the gravity stopping distance based on

(1) 115% of the rated speed where oil buffers are used, or 115% of the reduced striking speed when emergency terminal speed-limiting devices meeting the requirements of 2.25.4 are used and no provision is made to prevent the jump of the car at counterweight buffer engagement

(2) the governor tripping speed where spring buffers or elastomeric buffers are used (see 8.2.5 for gravity stopping distances)

(e) the distance to which the compensating-rope tiedown device, if provided (see 2.21.4.2), limits the jump of the counterweight when the car strikes the buffers at speeds specified in (d) plus the distance to account for the amount of compensation rope stretch