There is a lot of confusion about the chainsaw protection standards and how they vary around the world.

Type C, Class 1, chainsaw fabric layers, chainspeed, test methods ….

Understanding the global chainsaw protection standards is becoming increasingly important as arborists explore work opportunities in different countries and as arborist retailers start shipping outside their home country.

We thought that it was time to put a comprehensive guide to chainsaw protection standards together. Grab your popcorn and read on.

The Two Main Global Chainsaw Protection Standards

Broadly speaking, all of the current global standards for chainsaw protective legwear can be classified under two headings: European and North American. 

• European: currently this is ISO 11393, published in 2018, which replaced EN381
• North American: The USA standard,ASTM F1897, is the main document for North America so will be referred to in this paper.

The standards under either of these headings specify the general requirements for design and construction, the protective coverage areas, the performance testing needed, the certification process and the labelling and marking information required.

The Australian/New Zealand standard, AS/NZS 4453 and the Japanese standard JIS T 8125: 2022 are virtually direct copies of ISO 11393, so for the purposes of this paper these will be grouped under the European heading.

The Canadian standard, ASTM F3325, is very similar to ASTM F1897 so comes under the North American heading

A. The European standard ISO 11393

This standard has several parts to it covering footwear, legwear, hand and upper body protective garments.

Part 1 outlines the construction of the test rig for performing chainsaw cut tests

Part 2 outlines the test methods and the performance requirements for the leg protectors themselves.

Note : EN381 was superseded by EN ISO 11393 effective 19 November 2021. One of the main changes was the replacement of Design B with a new chaps design. Chainsaw chaps were not previously included in the European standard. Garments certified to EN381 are still able to be used up to the expiry of their certificate (5 years after the certification date).

The Australian/New Zealand standard AS/NZS4453.3

The AS/NZS standard is largely a copy of the ISO 11393 standard, with some subtle differences:

1. ISO 11393 includes 3 different classes of chainspeed testing; Class 1 at 20 m/s, Class 2 at 24 m/s and Class 3 at 28 m/s.  AS/NZS4453.3 only has one level of chainspeed testing which is 20 m/s.
2. ISO 11393 outlines the coverage areas for three different designs of leg protectors, Design A trousers – frontal protection; Design B chaps – frontal protection and Design C trousers – frontal and rear protection. AS/NZS4453.3 has adopted Design A only for the trouser style with one very minor modification and its chaps design is similar to Design B.  These designs will be looked at closely later.

B. The North American standard ASTM F1897 – 20

This standard outlines the performance requirements for leg protection, while the test methods for testing to this standard are given in ASTM F1414. 

What are the main differences between these two standards?

The requirements for leg protectors specified by both standards are given in the table below.  While these differences may appear insignificant, the two standards produce completely different results and consequently there is no direct correlation between them.

	ISO 11393 Parts 1 & 2	ASTM F1897-20 & F1414
Various tests required	Dimensional change (shrinkage) Chainsaw cut testing Protective area checking Attachment strength of chainsaw pad to garment Innocuousness Ergonomics	Chainsaw cut testing
Preconditioning of test samples	5 times specified washing and drying procedure	5 times specified washing and drying procedure
Requirements for dimensional change	Less than 6% for both length and width	No requirement
Requirements for protective area	Trousers Design A: covers from 20cm above crotch to 5 cm above hem with an extra 5 cm of protection wrapping around on the left side of each leg. Chaps Design B: as for trousers Design A Trousers Design C: Front protection from 20 cm above the crutch to 5 cm above the hem with rear protection from 5 cm below the crutch to 5 cm above the hem.	Pants/Trousers: a minimum length of 700 mm (28”) covering from the crutch to 7.5 cm (3”) above the hem with an extra 0.524 rad (30°) or 100mm (4”) wrapping around to the left of each leg. (Note that 30° equates to approx 6 cm at the top of the thigh.) Chaps: a minimum length of 700 mm (28”) covering from the crutch to 25mm (1”) above the carrier garment.  Minimum width of 350mm (14”) at the midpoint of the pad and 250mm (10”) at the bottom of the pad.
Requirements for fastenings for chaps	Minimum of 4 straps with a maximum distance of 200mm between straps. One strap must be at the top of thigh and another must be at the bottom of hem.	No specification for number of straps or placement
Requirements for pad attachment strength	150N force	No requirement, but does state that “the protective pad shall be permanently attached to the protective clothing”.

What are the differences between the test methods for these two standards?

The cut-test methods used by both standards are given in the table below.

	ISO 11393	ASTM F1414
Drive unit for test rig	Electrically powered motor driving a flywheel of specified inertia	Standard gasoline powered chainsaw with standard clutch mechanism.
Performed on	Actual garments	Rectangular pads made up in the materials intended to be used. Calibration pads are specified as 200mm x 700mm, however actual test pads are accepted in varying dimensions.
Number of tests	Design A and B. 6 cuts 3 on each leg. Design C. 8 cuts, 2 cuts on each leg on both front and rear.	24 cuts on test pads
Angle and position of cut tests	All cuts after preconditioning are made at 45° in the knee area with the chain moving upwards from left to right of the leg.	Cuts are made in the centre of the test pads consisting of: – 6 cuts without preconditioning at 45° – 6 cuts without preconditioning at 90° – 6 cuts after preconditioning at 45° – 6 cuts after preconditioning at 90°
Status of power at point of release	Power disengaged from flywheel allowing inertia of flywheel to continue driving the chain.	Power remains on
Height above pad at point of release	3mm	50mm (2”)
Distance from point of contact to centre of drive sprocket	130mm	130mm
Downward force at point of contact	15N	15N
Chain type	8mm, 0.325” pitch	10mm, 0.375” pitch
Bar	330mm, (13”) with 11 tooth nose sprocket	500mm (20”) with 11 tooth nose sprocket
Drive sprocket	7 tooth	7 tooth
Method of fixing of test specimen	A row of spikes 30mm apart penetrate the specimen for a length of 800mm on the opposite side of the specimen from the drive unit. The spikes are omitted for a distance of 60 mm each side of the contact point.  Masses of 250g every 100mm are used to hold specimen in place over the specimen holder.	2 plates 75mm x 25mm with centrelines 290mm apart are clamped up tight on to specimen. Clamps are on the opposite side of specimen from drive unit.  No mass is used to pull pad taut over the specimen holder.
Chainspeed requirement	20 m/s 24 m/s 28 m/s	2750 ft/min
Reporting method	Pass or fail at the nominated chainspeed.  Cut-through is deemed to be if there is any damage to the innermost layer (lining) of the garment.	All 24 pads tested must show no cut-through at this chainspeed. Cut-through is deemed to be any cut in the lining fabric.

Important considerations of these comparisons.

• Both standards report the results of cut-testing simply as a pass/fail to the nominated level of chainspeed, therefore no indication is given of the margin of safety that exists of a particular garment above that minimum level.  (Under the F1897 standard, Underwriters Laboratory, who are the certifying body, used to be able to perform a ‘CS50’ test which determined the point at which cut-through was likely to occur.  This was useful as it gave a means of comparing the performance level of different garments, however UL have decided to cease doing this type of testing.)
• Certification of a garment by a certifying body means that the garment is certified, or has a third party verification, that it will pass at the minimum level as specified in the standard.  The certification process involves auditing of a manufacturer’s production processes to ensure that each garment will meet the standard.
• There are multiple significant differences between the test methods of ISO 11393 and ASTM F1414-20. These include:
  • The drive mechanism
  • the status of the power at point of release
  • the release height above the test specimen
  • the method of fixing the specimen to the holder
  • the size of chain and angle of cuts

All of these mean that there is no correlation between the two standards.  Simply converting m/s to ft/min mathematically to compare performance should not be done as it is highly misleading.

• The European standard cut testing is performed on an actual garment, although the garment is prevented from rotating on the specimen holder by means of the spikes.  The ASTM standard cut tests are performed on test pads which are only representative of the final product.
• Both standards state that the protective pad must be permanently attached to the garment, however ASTM F1414-20 has no test to determine how well the protective pad is held in place in the carrier garment.  The European standard does have a strength test for this.

The Canadian standard ASTM F3325-20.

ASTM F3325-20 is the current standard for Canada, excluding BC and gives the performance requirements for chainsaw protective garments.  While it is virtually a copy-and-paste from ASTM F1897-20, it does include some other options for the design of garments.

ASTM F3324 gives the test methods for ASTM F3325 and apart from some minor differences it is identical to ASTM F1414, so testing performed is interchangeable between standards.

Importantly, ASTM F3325-20 replaced the withdrawn standard BNQ 1923.  This change established a much-needed alignment between the Canadian and USA standards.  Both countries’ standards now share the same test methods, certification processes, marking and labelling requirements.  This will make it easier for companies who carry out work on both sides of the border as the same garment will more likely be able to be certified to both standards.  However, note that there is still a chainspeed difference.

The table below gives an outline of the main differences for the requirements of leg protectors for Canada and USA:

	ASTM F3325-20	ASTM F1897
Coverage area for pants and chaps	4 coverage area options: Category A: front protection plus rear calf protection Category B: front protection only Category C: front protection plus extensions to the left of both legs Category D: same as for ‘C’ but with rear protection as well	At front: from crotch level to 3” (7.5cm) above the hem, plus extensions to the left of both legs.   No provision for rear protection
Fastenings for chaps	States that straps must be permanently attached. Certain placement positions are specified.	States that there must be adequate means of holding the garment securely around the leg. There is no specification for placement.
Chainspeed for cut-testing	3000 ft/min	2750 ft/min

The Worksafe BC Standard

This standard, Worksafe BC Schedule 8-A, section 8.21, has been adapted from the original WCB (Workers Compensation Board) standard PPE 1 – 1997.

At that time there was a test rig commissioned to test to this standard based in BC, which was similar to the test rig described in ASTM F1414, but with one notable difference, namely that the specimen holder was free to rotate around its axis.  This meant that the chain engaged with fresh protective fabric as it rotated when under test, whereas with ASTM F1414 the chain digs deeper into the same place, because the specimen holder is not free to rotate.  Consequently, the ASTM F1414 test method is considerably more rigorous.

This BC test rig was decommissioned some years ago when the owner/operator died and the rig was sold to a legwear manufacturer.  It is no longer available for public use.

The requirements for leg protectors under this Worksafe BC standard are similar to both ASTM F3325 and its predecessor BNQ 1923, however it only allows for one design of garment which is the equivalent of Category C in ASTM F3325.

Unusually, it allows for four different ways of complying with the cut test requirements:

1. Achieving a threshold chainspeed of 3600 ft/min when tested using the test rig for WCB PPE 1 – 1997
2. Achieving a threshold chainspeed of 3300 ft/min when tested according to ASTM F1414.
3. Meeting EN381-5 at the chainspeed level of 24 m/s
4. Meeting ISO 11393-2 (same as EN381-5) at the chainspeed level of 24 m/s.

It is to be noted that chainsaw operators and companies in BC generally refer to the minimum chainspeed needed to comply as 3600 ft/min.  What is not understood is that this speed has reference to a test method that is no longer available.

Therefore Option 2 is the most feasible option for manufacturers to comply with this Worksafe BC standard, which is 3300 ft/min when tested according to ASTM F1414.

Conclusion

In summary, there are a number of very significant differences between chainsaw protection standards globally and consequently the results obtained using one test method cannot be translated over to the other. 

The common theme in these different test methods is that they are designed to create a benchmark test by which different manufacturer’s product can be compared.

While neither are perfect, both the European and the North American standards are designed to outline a minimum performance level for leg protectors with the object of protecting chainsaw users from the horrific injuries that are the result of a chainsaw accident.

Appendix

Coverage Areas for the various standards

The coverage areas specified by the various standards have been given in the tables above, but it will be helpful to show these in visual format.

ISO 11393: Specifies 3 different coverage areas given as Design A, B or C.  Designs A and C relate to pants and Design B to chaps.

ASTM F1897: Has one specification for pants and another for chaps.

ASTM F3325: Has four options available for both pants and chaps.

Worksafe BC Standard: Has one option for both pants and chaps.

AS/NZS 4453: Has one specification for pants and one for chaps.