Investigation Guideline

Appendix 87
February 15, 1990
Revised
AUTOMATIC RESIDENTIAL GARAGE DOOR OPERATORS
I.

INTRODUCTION

A.

Background Information

Most entrapment incidents involved children between 2 and 4
years-of-age whose chest depths range between 3.9 and 5.6 inches.
It appears that the garage doors are contacting the child at more
than 2 inches from the ground and not reversing. Two related
events may be responsible for entrapment: 1) the closing door
contacting the child's chest may not meet sufficient resistance
to trigger the reversal mechanism and thus continues to close; or
2) improperly installed or adjusted bottom limit switches, or
floor settlement may increase the two-inch space so that the
automatic reverse mechanism disengages at a higher point.
The voluntary standard for automatic garage door operators
is maintained by Underwriters Laboratories (UL). The standard,
entitled "UL 325, Standard for Safety for Door Drapery Gates,
Louvre and Window Operators and Systems was first published on
April 1, 1973. It was revised in April 1975 and revised again,
effective April 1982 to address the hazard of child entrapment.
After April 1975, the voluntary standard required that the
garage door reverse if a downward moving door contacted an object
for more than two seconds except during the last two inches of
downward travel. The two-inch exception was allowed to prevent
false reversals due to small obstructions at the base of the door
opening, such as stones or ice, and to allow for movement of the
pavement due to frost heave. However, entrapment incidents
continued to occur even with automatic garage door operators
having the automatic reverse feature.
The revisions to the standard, effective April 1, 1982,
eliminated the exception allowing de-activation of the automatic
reverse mechanism during the last two inches of downward motion.
The conformance test procedure was also changed. A fully
installed door system must be tested instead of only the
operator, as previously allowed. Door reversal must occur within
two seconds of contacting a two inch test object whose top inch
is resilient and whose bottom inch is rigid. In addition, the
April 1982 revision required that the door reopen if the bottom
limit switch is not activated within 30 seconds after the control
is pressed to start the closing cycle. The Commission staff will
monitor and evaluate their latest revision. Investigation of
automatic garage door operator injuries are needed to support
this effort.

Appendix 87
February 15, 1990
Revised

B.

Product Class Description
1.

Definitions and General Description

Residential garage door operators consist of electricallypowered drive mechanisms, mounted on the ceiling of garages,
which are activated by wall switches and in some cases, remote
portable battery-powered transmitter switches. Some of these
mechanisms employ momentary contact buttons that must be pushed
and released to operate the door. Some units, particularly those
manufactured prior to the 1982 revision of the standard, required
constant contact pressure on the buttons. On those with a
momentary contact button, a second push on the switch, when the
door is operating in the down cycle, may either reverse or stop
the door, depending on the design. On the up cycle, a second
push may stop, reverse, or have no effect on the door motion.
(The new UL standard specifies that a push on the button during
the up cycle should not reverse the motion of the door.) For
doors that stop with a second push, the third push will either
reverse the motion or resume the motion in the original
direction.
The automatic reverse mechanism reverses the direction of
the closing garage door when the door becomes blocked. The
sensing mechanism detects increases in resistance to the moving
door. When the resistance exceeds a threshold, which is
adjustable, the mechanism reverses the drive motor.
The force adjustment regulated the force with which the door
descends. The force adjustment should be set as low as possible
and yet still adequately close the door. Then, when the door
meets a blockage, the door will reverse. If the force adjustment
is set to high, the blockage may go unnoticed.
The bottom line switch determines when the drive motor cuts
off. This, in turn, determines the reference point at which the
automatic reverse mechanism disengages. The bottom limit switch
should be set so that the motor cuts off when the door is
contacting the ground. If the bottom limit switch is adjusted
improperly, or if the ground settles, the motor may cut off
before the door reaches the ground. This additional space, when
added to the automatic reverse disengagement height, may allow
room for a child to become entrapped under a closing door.
The manual disconnect feature is a means to manually detach
the door operator from the door, so that the door may be raised
or lowered manually. It usually consists of a pull rope.
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Appendix 87
February 15, 1990
Revised

II.

INSTRUCTIONS FOR COLLECTION SPECIFIC INFORMATION

A.

Synopsis

A description of the sequence of events, the type of door
and operator mechanism, and the conditions existing at the time
of the accident are necessary to determine the major hazard
patterns and the risk of injury associated with residential
garage door operators.
B.

Description of Victim Contact With the Product
(Victim/Product/Environment Interface)

Determine the accident sequence and the exact position where
the door contacted the victim (chest, back, neck, etc.) and the
dimensions of the body part(s) affected. Be sure to note whether
child was facing into or out of the garage, and whether child's
front was facing up or down. In addition, note where under the
door the child was found (left side, middle, right side), and
provide sketches and dimensions.
C.

Instructions for Collecting Specific Information
1.

Information Collection

Determine the manufacturer and age of the unit and by whom
it was installed (mechanic, homeowner, etc.). It is particularly
important to determine if the opener was installed before or
after April 1, 1982.
Describe the location (note dimensions) and principles of
operation of the garage door operator components (see attached
diagram) including the following:
o

Wall switch

o

Bottom limit switch

o

Radio transmitter remote control

o

Automatic reverse mechanism
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Appendix 87
February 15, 1990
Revised

o

Types of sensing mechanism and switches

o

Force adjustment mechanism

o

Obtain in detail the operating history of the
garage door.

o

Determine how recently the reverse mechanism was
checked/observed to be functioning correctly.

o

Describe any previous problems with door
operation. Use pictures and sketches if
appropriate.

o

Describe any maintenance, adjustments, and/or
repair. Determine who made them (mechanism,
installer, owner, etc.), when made, and operation
of door after changes.

o

Obtain copies of any investigations of the
incident prepared by the police, coroner,
manufacturer, installer, law firm, insurance
company or engineering firm.

Visually examine the garage door system including the door
hardware and door opener hardware. Look for signs of loose or
broken attachments, bending or buckling, binding, or similar
signs of damage, misalignment or other problem. Report presence
or absence of such problem. If damages or other problems are
noted, do not perform the operational observations discussed
below.
Inspect the door opener mechanism, owners manual or
other available material for the UL label. Report presence
of absence of the label. Photograph label and transcribe
information on the label.
Inspect the door opener and manual for information on the
manufacturer, make, model, serial number and similar data.
Photograph and transcribe this identifying information.
Inspect the doorway for any signs of settlement, heaving or
similar displacement from original condition. Inquire about
homeowner's knowledge of any such displacement, when it occurred
and of any corrective action was taken. Particularly ask if any
adjustments were made to the door opener, to the location of the
connecting arm bracket on the door, or to the door.
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Appendix 87
February 15, 1990
Revised

2.

Operational Observations
(a)

Determine whether or not the owner has used
and/or adjusted the garage door opener since
the accident and whether or not the owners or
their legal representatives would object to
routine operation of the system to permit
on-site observations.
(b) Ask the owner to perform the following
operational checks:
(1) Close the garage door and reopen it
using the wall-mounted switch. Note
whether or not the motor shuts off at
both the fully closed and open
positions. At the closed position
describe any space left under the door
at the right, left and center of the
door as you face the door from inside
the garage.
(2) Repeat above operations using the
remote operator, if available.
(3) Close the door using the
wall-mounted switch. Operate the manual
disconnect mechanism. Note whether or
not the trolley disconnects from the
rail. Attempt to manually open the door
to the full open position. Close the
door using the wall mounted switch.
Note whether or not the trolley
re-engages automatically, if not,
consult owner's manual for instructions
on properly re-engaging the trolley.
(4) Wait 5 minutes then check operation
of the automatic reverse mechanism to
see if reversal occurs when the door is
closed on a 1 1/2 inch by 3 inch by 12
inch wood block placed on the ground in
line with the operator on the 1 1/2 inch
side, the 3 inch side, and the 12 inch
side. Do not leave the door in contact
with the wood block for longer than 4
seconds. Report results. Wait 5
minutes between each check.
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Appendix 87
February 15, 1990
Revised

If reversal occurs at 1 1/2 inches or 3
inches, do not check further. Do not
make any additional observations. Do not
attempt to make any adjustments on the
door. If the door fails to reverse and
the owner or the manual indicate the
door is equipped with this feature,
suggest that the owner have the unit
examined by an authorized dealer.
D.

E.

Description of Victim
o

Indicate the victim's age, sex, height, weight,
body measurements, clothing, competence reducing
factors (e.g., impaired vision, physical
handicaps, medication, alcohol use, etc.) and
knowledge of product.

o

Note the victim's activity prior to the incident
(if a child, whether the victim was playing with
other children, unsupervised by an adult, etc.).

o

Stipulate who was operating the garage door, if it
was not the victim.

o

Indicate type of clothing worn by victim.

Description of Environment

Characterize weather conditions at the time of the accident,
including lighting and ground conditions.
III. INSTRUCTIONS FOR PHOTOGRAPHING AND/OR DIAGRAMMING ACCIDENT
SCENE AND FACTORS RELATED TO THE ACCIDENT SEQUENCE

Photograph accident scene showing operator mechanism,
switches and controls, and presence of safety labeling.
IV.

INSTRUCTIONS FOR OBTAINING SAMPLES AND
DOCUMENTS RELATED TO THE INVESTIGATION

Garage door dimension measurements, clearance dimension
measurements, location of the victim and test results of
observing the operation of the door and manual disconnect
mechanism are to be appended to the investigation report.
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Appendix 87
February 15, 1990
Revised

Obtain copies of the operating and installation instructions
and repair history (if any) that are available and append them to
the investigation report.
Investigators may wish to provide the homeowner with a copy
of the attached safety precautions.

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Appendix 87
February 15, 1990
Revised

SAFETY PRECAUTIONS
The following safety precautions are recommended by the
Commission in order to minimize changes of a mishap or tragedy
involving automatic garage doors. 1/
1. Aside from prohibiting all "beat the garage door" games,
parents should warn children of risks of intentionally or
accidentally activating the automatic doors.
2. Many garage door openers have an automatic reverse
mechanism which stops or reverses the garage door upon impact
with an object. This mechanism can usually be adjusted for
sensitivity. Consult the owner's manual or dealer for
instructions.
3. Lubricate the garage door mechanism periodically to
reduce friction in accordance with the owner's manual. The easier
the door rolls on its track, the easier it is to adjust to
control for maximum sensitivity.
4. Homeowners should be aware of what to do in case of
entrapment. Devices which contain automatic reverse mechanisms
usually either stop or reverse the door when the control is
pressed again. In addition, most garage door openers have a
manual disconnect feature which enables the opener to be
disconnected so that the door may be raised or lowered manually.
5. Remove the pull ropes on the door which were intended to
manually raise and lower the door, as these ropes are not longer
of value. Removing the ropes eliminates another hazard for your
children.
6. Relocating all operating switches out of the easy reach
of children will make it difficult for youngsters to play with
the devices.
7. Lock all cars contain the radio controls which activate
the garage doors.

1/ These were previously cited in the CPSC memo, August/Sept.
1980, and in letters in Action Line Reporters.
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Appendix 87
February 15, 1990
Revised
GARAGE DOOR OPENER

1.
2.
3.
4.
5.
6.
7.
8.

Wall Mounted Switch
Garage Door Opener
Drive Mechanism
Door Track
Manual Door Disconnect
Header Attachment
Door Arm
Garage Door

9