(a) Where Required and Located.
(1)
The car of every elevator
suspended by wire ropes shall be provided with one or more approved car safety
devices of a type identified in section
3035(e). The
safeties shall be attached to the car frame, and one safety shall be located
within or below the lower members of the car frame (safety plank).
EXCEPTIONS: Existing elevators having a rise of not
more than 15 feet that were:
1.
Installed before January 1, 1925, or
2. Equipped with a safety device actuated by
the slackening or breaking of the hoisting cables.
(2) All car safeties shall be mounted on a
single car frame and shall operate only on one pair of guide rails, between
which the frame is located.
(3) See
Design section
3106 for details of approval of
safeties.
(4) Every type of
car-holding or counterweight safety device hereafter installed shall be field
tested before a permit to operate is issued. This test shall be witnessed by an
authorized representative of the Division of Industrial Safety, or the division
may accept reports of witnesses recognized as competent by the division. This
test shall demonstrate that the safety device will function as required by
section
3035(c).
(b) Duplex Safeties.
(1) Where two (duplex) safeties are provided,
the lower safety device shall be capable of developing not less than ½
of the force required to stop the entire car with rated load. See also Design
section
3100(b). Duplexed
safety devices shall be arranged so as to function approximately
simultaneously. Complete details of the car frame and the safety device linkage
shall be submitted to the division for approval.
(2) Type A or Type C safety devices shall not
be used in multiple (duplexed).
(c) Function and Stopping Distance of
Safeties.
(1)
The safety device, or
the combined safety devices where furnished, shall be capable of stopping and
sustaining the entire car with its rated load from governor tripping
speed. The weight of the entire car shall include any compensating
ropes, traveling cables, and any other attachments to the car.
EXCEPTION: Safeties of elevators equipped with
alternating current driving machines may have the full load test conducted at
normal down speed by tripping the governor by hand. See section
3036(a)(1) for
governor test required.
(2)
Type B safeties shall stop the car with its rated load from governor tripping
speed within the range of the maximum and minimum stopping distances as
determined by the formulas in Design section
3106(a)(1).
(A) Table 3035 C and Figures 3106 A1 through
3106 A7 show the maximum and minimum stopping distances for various governor
tripping speeds for reference.
(B)
The distance the car traveled, after the safety device began to engage the
rails until the car stopped, shall be measured by taking the average of the
four rail marks and deducting the length of the safety jaw or
wedge.
(3) During the
field test, the controls shall be arranged so that the full power in the down
direction shall be applied until the safety has fully applied.
(4) The field test on Type A safeties shall
include the inertia test as outlined in Design section
3106(c)(3)(A).
(5) The field test of counterweight safeties
actuated by a governor shall be conducted with no load in the car. See section
3035(d)(1) for
drop test requirements where counterweight safeties are not governor
actuated.
(6) A functional test may
be required when inspection of the safety parts reveals conditions that may
prevent the safety from operating as intended.
TABLE NO. 3035 C
Maximum and Minimum Stopping Distances Type B Car
Safeties With Rated Load, and of Type B Counterweight Safeties
Rated Speed in Feet Per
Minute |
Maximum Governor Trip Speed in Feet
Per Minute |
Stopping Distances in
Feet-Inches |
|
|
Minimum |
Maximum |
|
..........................0 to
125 |
..........................175 |
|
|
0-1 |
|
1-3 |
|
..........................150 |
..........................210 |
|
|
0-2 |
|
1-4 |
|
..........................175 |
..........................250 |
|
|
0-3 |
|
1-7 |
|
..........................200 |
..........................280 |
|
|
0-4 |
|
1-10 |
|
..........................225 |
..........................308 |
|
|
0-5 |
|
2-0 |
|
..........................250 |
..........................337 |
|
|
0-6 |
|
2-3 |
|
..........................300 |
..........................395 |
|
|
0-8 |
|
2-9 |
|
..........................350 |
..........................452 |
|
|
0-10 |
|
3-4 |
|
..........................400 |
..........................510 |
|
|
1-1 |
|
4-0 |
|
..........................450 |
..........................568 |
|
|
1-5 |
|
4-10 |
|
..........................500 |
..........................625 |
|
|
1-8 |
|
5-8 |
|
..........................600 |
..........................740 |
|
|
2-4 |
|
7-7 |
|
..........................700 |
..........................855 |
|
|
3-2 |
|
9-10 |
|
..........................800 |
..........................970 |
|
|
4-1 |
|
12-6 |
|
..........................900 |
..........................1085 |
|
|
5-1 |
|
15-3 |
|
..........................1000 |
..........................1200 |
|
|
6-3 |
|
18-6 |
|
..........................1100 |
..........................1320 |
|
|
7-6 |
|
22-4 |
|
..........................1200 |
..........................1440 |
|
|
8-11 |
|
26-4 |
|
..........................1300 |
..........................1560 |
|
|
10-6 |
|
30-11 |
|
..........................1400 |
..........................1680 |
|
|
12-2 |
|
35-7 |
|
..........................1500 |
..........................1800 |
|
|
14-0 |
|
40-10 |
(d) Counterweight Safeties. Where any space
below the hoistway is used for a passageway or is occupied by persons, or if
unoccupied is not permanently sealed against access, the following requirements
shall be conformed to:
(1)
Elevator
counterweights shall be provided with safeties conforming to the requirements
for car safeties.
EXCEPTIONS:
1.
Where otherwise specified in section
3035, counterweight safeties may
differ from car safeties.
2. For
rated speeds of not over 150 feet per minute, counterweight safeties may be
operated as a result of the breaking or slackening of the hoisting ropes and
may be of the inertia or other approved type without governors.
Every safety device applied as a result of the
slackening or breaking of the hoisting cables shall be drop tested when
installed. This test shall be witnessed by a representative of the Division of
Industrial Safety, or the Division may accept reports of witnesses recognized
as competent by the Division.
3. Existing counterweights equipped with
safety devices actuated by the breaking or slackening of the counterweight
ropes and which have a rated speed of not more than 250 feet per
minute.
4. Wedge clamp safeties
shall not be used for counterweight safeties unless they are arranged to be
reset from the pit or the machine room.
(e) Identification and Classification of
Types of Safeties. Car safety devices (safeties) are identified and classified
on the basis of performance characteristics after the safety begins to apply
pressure on the guide rails. On this basis, there are three types of safeties.
(1) Type A Safeties. Safeties which develop a
rapidly increasing pressure on the guide rails during the stopping interval,
the stopping distance being very short due to the inherent design of the
safety. The operating force is derived entirely from the mass and the motion of
the car or the counterweight being stopped. These safeties apply pressure on
the guide rails through eccentrics, rollers, or similar devices, without any
flexible medium purposely introduced to limit the retarding force and increase
the stopping distance.
(2) Type B
Safeties. Safeties which apply limited pressure on the guide rails during the
stopping interval, and which provide stopping distance that are related to the
mass being stopped and the speed at which application of the safety is
initiated.
Retarding forces are reasonably uniform after the
safety is fully applied. Continuous tension in the governor rope may or may not
be required to operate the safety during the entire stopping interval. Minimum
and maximum distances are specified on the basis of governor tripping
speed.
(3) Type C Safeties
(Type A with Oil Buffers). Safeties which develop retarding forces during the
compression stroke of one or more oil buffers interposed between the lower
members of the car frame and a governor-operated Type A auxiliary safety plank
applied on the guide rails. The stopping distance is equal to the effective
stroke of the buffers.
(f) Safeties to Stop Ascending Cars or
Counterweights Prohibited. Safeties shall not stop an ascending car or
counterweight.
(g)
Governor Actuated Safeties and Car Safety Mechanism Switches Required.
(1)
Car safeties and counterweight
safeties, where provided shall be actuated by separate approved
governors.
EXCEPTIONS:
1.
Speed governors are not required for the operation of counterweight safeties of
elevators having a rated speed of not more than 150 feet per minute.
2. Existing elevators that comply with the
exceptions to section
3035(a)(1).
(2)
Car safeties shall be provided
with a switch, operated by the car safety mechanism when the safety is
applied.
EXCEPTION: Existing elevators which comply with the
exceptions to section
3036(d)(2).
(h) Limits of Use of Various Types of
Safeties.
(1) Type A (Instantaneous) Safeties.
Type A safeties may be used on elevators having a rated speed of not more than
150 feet per minute. When overspeed occurs, with the hoisting ropes intact,
such safeties shall be actuated by the governor.
On the parting of the hoisting ropes (free fall), Type
A governor-operated safeties shall apply without appreciable delay; and their
application shall be independent of the speed action of the governor and of the
location of the break in the hoisting ropes (inertia application) and may be
accomplished by the use of a governor and governor rigging having a
sufficiently high value of inertia to apply the safety on free fall
independently of the speed action of the governor.
(2) Type C (Combination Instantaneous and Oil
Buffer Safety). Type C Safeties may be used subject to the following
requirements:
(A) The rated speed shall be not
more than 500 feet per minute.
(B)
The oil buffers shall conform to all requirements specified in Section
3031 for oil buffers, except that
the stroke shall be based on governor tripping speed and on an average
retardation not exceeding 32.2 feet per second per second.
(C) After the buffer stroke has been
completed, provision shall be made for an additional travel of plunger or
piston of not less than 10 percent of the buffer stroke to prevent excessive
impact on the buffer parts and the auxiliary safety plank.
(D) Where the distance between guide rails
exceeds 8 feet, the safety shall be provided with two oil buffers of
substantially identical calibration; and the buffers shall be so located as to
develop minimum stresses in the auxiliary safety plank during safety operation.
Buffers shall be located in line with and symmetrically
between the guide rails.
(E)
The auxiliary safety plank shall be so designed that the maximum stresses in
the plank shall not exceed those specified for similar car frame members in
Design section
3101(a)(4).
(F) The rail-gripping device of the auxiliary
safety plank shall be so arranged and connected as to prevent the plank from
being out of level more than ½ inch in the length of the plank when the
safety is operated to stop the car.
(G) An electric switch shall be provided and
so arranged and connected that the elevator cannot be operated by means of the
normal operating device if any buffer is compressed more than 10 percent of its
stroke.
(H) Means shall be provided
to prevent operation of the elevator by means of the normal operating device if
the oil level in any buffer is below the minimum allowable
level.
(3)
No
car-holding safety device shall be used for a greater total load or speed than
that specified in the approval. The weight of the independent car
counterweights, where used, may be deducted from the total load of the car and
capacity in determining the load on the safety device.
(4) Observation elevators shall have safeties
of the type that do not require access to the car or hoistway for resetting.
Safeties on elevators exposed to the weather shall have corrosion resistant
parts of all points where corrosion could prevent the device from functioning
as intended.
(i)
Application and Release of Safeties.
(1)
Safeties shall be applied mechanically. Electric, hydraulic, or
pneumatic devices shall not be used to apply the safeties required by this
section, nor to hold such safeties in the retracted
position.
(2) The
application of the safety to stop the car, with its rated load centered on each
quarter of the platform symmetrically with relation to the center lines of the
platform, shall not cause the platform to be out of level more than 3/8 of an
inch per foot in any direction.
EXCEPTION: Type C safeties.
(3)
When car safeties are applied, no
decrease in tension in the governor rope nor motion of the car in the down
direction shall release the safeties; but such safeties may be released by the
motion of the car in the up direction.
(4) Safeties shall be so designed that on
their application the forces which provide the stopping action shall be
compressive forces on each side of the guide rail section.
(j) Minimum Permissible Clearance Between
Rail Gripping Faces of Safety Parts. In the normally retracted position of the
safety, the distance between the rail-gripping faces of the safety parts shall
be not less than the thickness of the guide rail plus 0.14 (
9/64 )
inch; and the clearance on any side between the gripping face and the guide
rail shall be not less than 0.0625 (
1/16 ) inch
as measured on the side of the rail toward which the car frame is pressed with
sufficient force to take up all clearances in the guide shoe assembly. Safety
jaws, while in the retracted position, shall be so restrained as to prevent a
reduction of this minimum clearance.
(k) Maximum Permissible Movement of Governor
Rope to Operate the Safety Mechanism.
(1) For
all drum-operated safeties, the movement of the governor rope, relative to the
car, required to operate the safety mechanism from its fully retracted position
to a position where the safety jaws begin to exert pressure against the guide
rails, shall not exceed the following values based on rated speed.
200 feet per minute or
less.......................... |
..........................42 inches |
201 to 375 feet per
minute.......................... |
..........................36
inches |
Over 375 feet per
minute.......................... |
..........................30
inches |
(2) Drum-operated car safeties, requiring
continual unwinding of the safety drum rope to fully apply the safety, shall be
so designed that not less than three turns of the safety rope will remain on
the drum after the overspeed test of the safety has been made with rated load
in the car.
(l) Minimum
Factors of Safety and Stresses of Safety Parts and Rope Connections. See Design
section
3106(d) for design
factors of safety.
(m) Corrosion
Resistant Bearings in Safeties and Safety Operating Mechanisms. Bearings in
safeties and of the safety operating mechanism shall be of corrosion-resistant
construction with one or both members of a bearing made of, or electroplated
with, a corrosion-resistant material.
(n) Marking Plates for Safeties. A metal
plate or plates shall be securely attached to each safety so as to be readily
visible, and shall be marked in a legible and permanent manner with letters and
figures not less than ¼ inch in height indicating the following:
(1) The type of safety.
(2) The maximum tripping speed in feet per
minute for which the safety is designed to be used.
(3) The maximum weight in pounds for which
the safety is designed to be used with the car frame in which it is
installed.
(4) The name of the
manufacturer and the identifying number of the safety.
(5) The date of the initial safety test
required by section
3035(a)(4)
witnessed by a representative of the division.
(o) Governor Rope Releasing Carriers.
The governor-rope releasing carrier on the car (or on the
counterweight) shall be set to require a tension in the governor rope, to pull
the rope from the carrier, of not more than 60 percent of the pull-through
tension developed by the governor; and the carrier shall be designed so that
the pull-out tension cannot be adjusted in a normal manner to
exceed the amount specified. Tension in the governor rope required to
pull the rope from the carrier shall not exceed 300 pounds.
(p) Rail Lubricants and Lubrication Plate.
Rail lubricants or coatings which will reduce the holding power of the safety
or prevent its functioning as required in section
3035(c) shall not
be used.
Where lubricants are to be used, a metal plate shall be
securely attached to the car crosshead in an easily visible location, and shall
carry the notation "CONSULT MANUFACTURER OF THE SAFETY FOR THE CHARACTERISTICS
OF THE RAIL LUBRICANT TO BE USED."
If lubricants other than those recommended by the
manufacturer are used, a safety test shall be made to demonstrate that the
safety will function as required by section
3035(c).
(q) Compensating Rope Tie Down. For rated
speeds of 800 feet per minute or more, a device shall be provided to tie the
car and counterweight together to limit the jump of the car or counterweight as
a result of buffer engagement or application of car or counterweight
safety.