Updates to the specification for Brushing Devices

Clarification Update

We have been asked to clarify the position on which brushes are approved for use in competition. All brushes that were approved for use at World Curling championships throughout the 2023–2024 season are still approved for use.

The active Approved Code List is available to download here. This list includes the Hardline and Goldline brushes in question.

As stated in the original announcement below, “This revised specification has been measured to include all the equipment in question. Those brush heads will remain on the World Curling Approved list.”

Original announcement

The World Curling Board has approved updates to the specification for Brushing Devices. This follows the discovery of problems with the application of testing protocols in the approval process of a selection of current brushes.

World Curling is responsible for establishing specifications for competition equipment and administering the approval and compliance processes for sweeping equipment.

Testing Facilities

Following the Sweeping Summit in 2016 and the resulting rules and specifications approved by the World Curling General Assembly that year, World Curling began testing new equipment using the facility involved with the Sweeping Summit.

A new testing facility was selected in 2019 after the Canadian National Research Council indicated they were unable to provide the testing on a long-term basis. Several tests were conducted, and approvals provided by this facility.

In 2023, it was discovered that this second facility had ceased trading without informing World Curling.

A third testing agency was then appointed. Early in 2024, several samples of brush heads used in the field of play at various events were sent to this facility for testing. This was followed with samples taken at the World Championships and new equipment sourced from retail outlets.

Product Issues

Testing from this new facility indicated that some heads in use did not comply with all the specifications and were therefore out of scope.

Following further investigation and discussion with the companies involved, when these specific products were tested for conformance and approved by the previous—now out of business facility—the accuracy of the testing protocol came under question indicating that these heads should not have been approved.

The products impacted are the Goldline Impact foam and the Hardline competitive foam. These products were found to be out with the compression modulus measure in the specification.

Impact on event results

For the results from events using the equipment in question, World Curling have determined the following:

World Curling has seen no evidence manufacturers intended to produce equipment outside established specifications and both have cooperated with our review.

Teams competing in events requiring World Curling approved equipment rely on equipment certified for use in World Curling events. There is no evidence that any of the tested equipment was altered post-production in any way.

The failed specification in question was the Compression Modulus specification. This is a calculation of the force required to compress the foam by 25% compared with the force required to compress the foam by 65%. Despite being outside the Compression Modulus specification, neither the force at 25%, nor the force at 65% are considered excessive when compared with other conforming products.

Therefore, unless further investigation contradicts the above items, the results of all events where this equipment was used is affirmed and further, there is no action being contemplated against any manufacturer in this situation.

World Curling have reviewed the specifications in use and will replace the compression modulus as indicated below.

This revised specification has been measured to include all the equipment in question. Those brush heads will remain on the World Curling Approved list.

This situation has demonstrated the need for a full review of the Specification for Sweeping Equipment.

Equipment Advisory Group

To facilitate this review, World Curling has tasked its newly created Equipment Advisory Group—which includes technical experts receiving advice and feedback from athletes, coaches, high performance experts, curling ice and stone experts and equipment manufacturers—with reviewing the specifications, testing protocols and monitoring processes that are in place.

New scientific methods of testing are being investigated with the intent of simplifying the process of to make it easier for manufacturers to comply with updated standards.

In particular, the Equipment Advisory Group will be looking at the following elements:

Distribution of force by the curling brush
Impact of age, storage and amount of use of foam in approved brush heads
Testing protocols for use at events
Ice impact images to determine specific impacts on the curling ice
Further use of product codes and identifying marks to ensure all individual components of sweeping devices can be properly identified and confirmed for compliance
Evolving sweeping techniques
Other factors at their sole determination

Revised Specifications

Should the work of the Equipment Advisory Group identify any elements which substantially conflict with the established principles of what sweeping a curling stone should be able to accomplish, World Curling reserves the right to take necessary action to secure competitive integrity, up to and including removal of equipment from the approved list.

The removal of the compression modulus as a measure to ensure foam is in scope

The addition of a new compression measure based on the compression at 779N

With immediate effect, all foam manufactured for use in sweeping equipment must include identifying marks that allow its year of production to be determined. These will be included in the approved list document along with picture of the approved heads and sleeves.

No new products will be approved after 1 January 2025 for use before the end of the 2025–2026 season. From 1 January 2025 new testing protocols are expected to be in place.

The updated Statement of Principles for Competition Equipment is available to download here.

World Curling apologises for the failures in the approval process and assure the curling community that with the assistance of our new testing company and the Equipment Advisory Group, a renewed focus on this area will be implemented. World Curling will deliver a simpler and more robust system that brings clarity for manufacturers and players alike.