--------------------+-------------------------------------------------------
Gross vehicle | Equipment Speed, MPH
weight lbs. |-------|-----|-----|-----|-----|-----|-----|-----|-----|-----|----
| 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20
--------------------+------+----+----+----+----+----+----+----+----+----+---
Service Brake Maximum Stopping Distance--Feet
--------------------+------+----+----+----+----+----+----+----+----+----+---
0-36,000............| 34 | 38 | 43 | 48 | 53 | 59 | 64 | 70 | 76 | 83 | 89
36,000-70,000.......| 41 | 46 | 52 | 58 | 62 | 70 | 76 | 83 | 90 | 97 |104
70,000-14,0000......| 48 | 54 | 61 | 67 | 74 | 81 | 88 | 95 |103 |111 |119
140,000-250,000.....| 56 | 62 | 69 | 77 | 84 | 92 |100 |108 |116 |125 |133
250,000-400,000.....| 59 | 66 | 74 | 81 | 89 | 97 |105 |114 |123 |132 |141
Over-400,000........| 63 | 71 | 78 | 86 | 94 |103 |111 |120 |129 |139 |148
--------------------+------+----+----+----+----+----+----+----+----+----+---
Stopping distances are computed using a constant deceleration of 9.66 FPS(super)2
and system response times of .5.1, 1.5, 2, 2.25 and 2.5 seconds for each of
increasing weight category respectively. Stopping distance values include a
one-second operator response time.
TABLE M-2.--THE SPEED OF A VEHICLE CAN BE DETERMINED BY CLOCKING IT THROUGH A
100-FOOT MEASURED COURSE AT CONSTANT VELOCITY USING TABLE M-2. WHEN THE
SERVICE BRAKES ARE APPLIED AT THE END OF THE COURSE, STOPPING DISTANCE CAN BE
MEASURED AND COMPARED TO TABLE M-1.
---------------------+----+----+----+----+----+----+----+----+----+----+---
Miles per hour | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20
+----+----+----+----+----+----+----+----+----+----+---
Seconds required to | | | | | | | | | | |
travel 100 feet.... | 6.8| 6.2| 5.7| 5.2| 4.9| 4.5| 4.3| 4.0| 3.8| 3.6|3.4
---------------------+----+----+----+----+----+----+----+----+----+----+---
(b)(3) Service brake tests shall be conducted under the
direction of the mine operator in cooperation with and according to the
instructions provided by the MSHA inspector as follows:
(b)(3)(i) Equipment capable of traveling at least 10 miles
per hour shall be tested with a typical load for that particular piece of
equipment. Front-end loaders shall be tested with the loader bucket empty.
Equipment shall not be tested when carrying hazardous loads, such as
explosives.
(b)(3)(ii) The approach shall be of sufficient length to
allow the equipment operator to reach and maintain a constant speed between
10 and 20 miles per hour prior to entering the 100 foot measured area. The
constant speed shall be maintained up to the point when the equipment
operator receives the signal to apply the brakes. The roadway shall be wide
enough to accommodate the size of the equipment being tested. The ground
shall be generally level, packed, and dry in the braking portion of the test
course. Ground moisture may be present to the extent that it does not
adversely affect the braking surface.
(b)(3)(iii) Braking is to be performed using only those
braking systems, including auxiliary retarders, which are designed to bring
the equipment to a stop under normal operating conditions. Parking or
emergency (secondary) brakes are not to be actuated during the test.
(b)(3)(iv) The tests shall be conducted with the transmission
in the gear appropriate for the speed the equipment is traveling except for
equipment which is designed for the power train to be disengaged during
braking.
(b)(3)(v) Testing speeds shall be a minimum of 10 miles per
hour and a maximum of 20 miles per hour.
(b)(3)(vi) Stopping distances shall be measured from the
point at which the equipment operator receives the signal to apply the
service brakes to the final stopped position.
(b)(4) Test results shall be evaluated as follows:
(b)(4)(i) If the initial test run is valid and the stopping
distance does not exceed the corresponding stopping distance listed in Table
1, the performance of the service brakes shall be considered acceptable. For
tests to be considered valid, the equipment shall not slide sideways or
exhibit other lateral motion during the braking portion of the test.
(b)(4)(ii) If the equipment exceeds the maximum stopping
distance in the initial test run, the mine operator may request from the
inspector up to four additional test runs with two runs to be conducted in
each direction. The performance of the service brakes shall be considered
acceptable if the equipment does not exceed the maximum stopping distance on
at least three of the additional tests.
(b)(5) Where there is not an appropriate test site at the
mine or the equipment is not capable of traveling at least 10 miles per hour,
service brake tests will not be conducted. In such cases, the inspector will
rely upon other available evidence to determine whether the service brake
system meets the performance requirements of this standard.
[53 FR 32528, Aug. 25, 1988; 53 FR 44588, Nov. 4, 1988]
