Ansi B 175.1-1991 Chainsaw Kickback Standard - Stihl 9 Instruction Manual

It may also occur during limbing.
The greater the force of the kickback
reaction, the more difficult it becomes for
the operator to control the saw. Many
factors influence the occurrence and
force of the kickback reaction. These
include chain speed, the speed at which
the bar and chain contact the object, the
angle of contact, the condition of the
chain and other factors.
The type of bar and saw chain you use
is an important factor in the occurrence
and force of the kickback reaction.
Some STIHL bar and chain types are
designed to reduce kickback forces.
STIHL recommends the use of reduced
kickback bars and low kickback chains.
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Section 5.11 of ANSI standard B 175.1–
2000, sets certain performance and
design criteria related to chainsaw
kickback.
To comply with section 5.11 of ANSI B
175.1-2000:
a) saws with a displacement of less than
3.8 cubic inches
– must, in their original condition,
meet a 45° computer derived
kickback angle when equipped with
certain cutting attachments.
– and must be equipped with at least
two devices to reduce the risk of
kickback injury, such as a chain
brake, low kickback chain, reduced
kickback bar, etc.
b) saws with a displacement of 3.8 cubic
inches and above
– must be equipped with at least one
device designed to reduce the risk
of kickback injury such as a chain
brake, low kickback chain, reduced
kickback bar, etc.
The computer derived angles for saws
below 3.8 cubic inch displacement are
measured by applying a computer
program to test results from a kickback
test machine.
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The computer derived angles of § 5.11 of
ANSI B 175.1-2000 may bear no rela-
tionship to actual kickback bar rotation
angles that may occur in real life cutting
situations.
In addition, features designed to reduce
kickback injuries may lose some of their
effectiveness when they are no longer in
their original condition, especially if they
have been improperly maintained.
Compliance with § 5.11 of
ANSI B 175.1-2000 does not automatic-
ally mean that in a real life kickback the
bar and chain will rotate at most 45°.
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inch displacement to comply with the
computed kickback angle requirements
of § 5.11 of ANSI B 175.1-2000 use only
the following cutting attachments:
– bar and chain combinations listed as
complying in the "Specifications"
section of the Owner's Manual or
– other replacement bar and chain
combinations marked in accordance
with the standard for use on the
powerhead or
– replacement chain designated
"low kickback saw chain''.
See the section on "Low kickback saw
chain and reduced kickback bars"