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 increasing 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.
1. The Two Main Global Chainsaw Protection Standards
Broadly speaking there are 2 global standards.
- European EN381
- North American ASTM F1897
The Australian/New Zealand standard is almost a direct copy of the EN381, so for the purposes of this paper it will be grouped under that document. The small differences are outlined later.
The Canadian standards are related to F1897 and will be discussed as a subset of that standard.
a. The European standard EN381
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 to be performed on leg protectors.
Part 5 gives the requirements for leg protectors, i.e. the coverage areas, general construction details, the performance testing needed and the labeling and marking information required.
The differences between EN381.5 and the Australian/New Zealand standard, AS/NZS4453.3
- EN381.5 only allows for trouser type garments incl. leggings, not chaps that buckle at the rear of the leg, whereas AS/NZS4453.3 allows for both types.
- EN381.5 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.
- EN381.5 outlines the coverage areas for three different designs of trousers, Design A, Design B and design C, whereas AS/NZS4453.3 has adopted Design A only with one very minor modification. These designs will be looked at closely later.
b. The North American standard ASTM F1897 – 14
This standard outlines the requirements for leg protection, i.e. general requirements for design and how they are made, the protective coverage areas, the performance testing needed, the certification process, the care and maintenance guidelines and the labeling and marking information required.
The test methods for testing to this standard are given in ASTM F1414 – 13.
c. Comparison of the requirements and the test methods for both of these standards.
The requirements and the test methods employed by both standards are given in the table below. While these differences may appear insignificant, the two standards produce completely different results and the meaning of the results are not comparable, consequently there is no direct correlation between them.
i. Requirements
| EN381 | ASTM F1897 & F1414 | |
| Various tests required | Dimensional change (shrinkage), chainsaw cut testing, protective area checking, attachment strength of chainsaw pad to garment | 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 20 cm above crotch to 5 cm above hem with an extra 5 cm of protection wrapping around on the left side of each leg. Trousers Design B: as for Design A but with an extra 5 cm wrapping around 5 cm to the right of the left leg 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 covering from the crutch to 7.5 cm (3”) above the hem with an extra 0.524 rad (30°) or 100 mm (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 25 mm (1”) above the carrier garment. Minimum width of 350 mm (14”) at the midpoint of the pad and 250mm (10”) at the bottom of the pad. |
| Requirements for pad attachment strength | 200N force | No requirement |
ii. Testing Methods
| EN381 | ASTM F1897 & F1414 | |
| Drive unit for test rig | Electrically powered motor with a clutch and 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 | 6 cuts, 3 on each leg for Design A, and 2 cuts on each leg on both front and rear for Design C. | As many as are required to determine the threshold chainspeed, usually 24. |
| Angle and position of cut tests | All cuts after preconditioning, 45° in the knee area with the chain moving upwards from left to right of the leg. | In the centre of the test pads. Usually, those performed are: 6 cuts without preconditioning at 45°, 6 cuts without preconditioning at 90°, 6 cuts after preconditioning at 45°, and 6 cuts after preconditioning at 90°. |
| Status of power at point of release | Power released | 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 |
| 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 75 mm x 25 mm with centrelines 290 mm 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. |
| 20 m/s or 24 m/s or 28 m/s | 2750 ft/min | |
| Reporting method | Pass or fail at the specified chainspeed. Cut-through is deemed to be if there is a cut of greater than 10mm in the lining material. | There are two reporting methods. The first method is to evaluate a simple pass/failure at a specified chain speed e.g. 2750 ft/min. All 24 pads tested must show no cut- through at this chain speed. The second determines a threshold chain speed or CS50 which is the speed at which the probability of cut- through is 50%. Cut-through is deemed to be any cut in the lining fabric. |
Comparing Test Methods
- The European standard reports the results of cut-testing simply as a pass/fail to a minimum level of chainspeed, therefore no indication is given of the margin of safety that exists of a particular garment above that minimum level. The CS50 determination as reported under F1897 does give a direct comparison of the performance of different garments which is useful. Bear in mind that this CS50 determination is an additional test procedure that must be requested from Underwriters Laboratory (UL) and does not constitute part of the certification process. Certification of a garment by UL means that the garment is certified to pass at the minimum level as specified in the standard.
- The main differences between the two standards, power status, height above test specimen, fixing methods, size of chain and angle of cuts, all mean that there is no correlation between the two. Simply converting m/s to ft/min mathematically to compare performance should not be contemplated.
- 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.
- It is noted that there are no tests performed to determine how well the protective pad is held in place in the carrier garment with the ASTM F1897 standard.
Understanding the Canadian and US Standards
The Canadian standards are complex.
The BNQ 1923-450-M91 standard was actually withdrawn some years ago but has continued to be used as the main Canadian standard. As of August 2018, a replacement has been issued, ASTM F3325 – 18. The test method for BNQ 1923-450-M91 was specified in BNQ 1923-450-M90 which has now been replaced by ASTM F3324 – 18.
Apart from some minor differences F3324 is identical to F1414 so testing performed is interchangeable between standards.
The main differences between the BNQ 1923 standard and ASTM F1897 are:
- BNQ 1923 provides for 3 different designs for both chaps and trousers with varying coverage areas. Category A covers the frontal area from the crutch to 75mm above the hem plus the rear of the leg from the knee to the ankle. Category B is just the front only from the crutch to 75mm above the hem. Category C is the frontal area from the crutch to 75mm above the hem plus an area wrapping around to the left of both legs of 100mm. The confusing part of this that a European Design A does not have calf protection but the Canadian Category A does. References to “Type” A and C (which does not actually exist) confuse the issue even further.
- BNQ 1923 requires a minimum chainspeed of 3000 ft/min when tested according to BNQ 1923-450-M90, compared to F1897 with 2750 ft/min.
The new Canadian standard F3325 gives a lot more detail to the coverage areas specified than its predecessor, e.g. the length of the rear area of the pad for Category A must be 305mm (12”). The wording resembles F1897 so that the two standards are much more closely aligned. F3325 adds another category to the possibilities for coverage area, Category D which is a combination of A and C. It also includes some specification around the placement of straps on chaps.
British Columbia
Worksafe BC Schedule 8-A, section 8.21 is adapted from the original WCB (Workers Compensation Board) standard PPE 1 – 1997. This Worksafe BC standard is similar to BNQ 1923, however it only allows for one design of garment which is the equivalent of Category C.
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 F1414, but with one notable difference, namely 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 F1414 the chain digs deeper into the same place as it is not free to rotate. The effect of this difference is that BC test rig returned significantly higher chainspeed results. This 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.
Unusually, Worksafe BC Schedule 8-A, section 8.21 allows for four different ways of complying with the cut test requirements:
- Achieving a threshold chainspeed of 3600 ft/min when tested using the test rig for WCB PPE 1 – 1997
- Achieving a threshold chainspeed of 3300 ft/min when tested according to ASTM F1414.
- Meeting EN381-5 at the chainspeed level of 24 m/s
- 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 generally refer to the minimum chainspeed needed to comply as 3600 ft/min. What is not understood is that this speed refers to the test method used with the old BC test rig that is no longer available. The applicable chainspeed test speed in BC is 3300 ft/min when tested according to F1414.
Conclusion
In summary, there are very significant differences between chainsaw protections standards globally and the results obtained using one test method cannot be translated over to the other.
Both test methods are designed to create a benchmark test by which to compare different manufacturer’s product and this they do. While neither are perfect, both standards are designed to outline the minimum requirements of leg protectors with the object of protecting chainsaw users from horrific accidents.