When is the Head Injury Assessment (HIA) used, and can I use it at a club or school match?

Only in elite adult matches and tournaments that World Rugby has approved in advance for the HIA (SARU Concussion Regulations, section 4). Approval needs, among other things, the Core Concussion Player Welfare Standards, an HIA review process and access to match video.

• At every other level, including club, school and U19 rugby, players must be managed with Recognise and Remove. An off-field HIA1 screen must not be used to decide whether a player can go back on.
• U19 players who qualify for an approved elite adult tournament (including approved U20 competitions) may be assessed under the HIA there.
• Only a registered medical doctor who has completed World Rugby's Medical Protocols for Match Day Medical Staff and Concussion Management for Elite Match Day Medical Staff modules may run the HIA.

Temporary replacement (Law 3.27): in an HIA-approved match the player must leave and be temporarily replaced, even if all replacements have been used, and play cannot restart until that happens. If the player has not returned 12 minutes (actual time) after leaving the playing area, the replacement becomes permanent.