There is a lot of conflicting information out there on AFFF systems ability to tolerate freezing temps.. We play it on the safe side. The bottle comes out of the car and lives in the house all winter.
RSB has done the research and has found a semi-local supplier who will discharge/flush/recharge and re-certify the bottle. The question here is that according the rulesthe bottle has to be fully charged, but there is no requirement that it has to be within the certification dates: .
3.F.3 Onboard Fire Suppression System or Extinguisher. LeMons EXCEEDINGLY STRONGLY recommends a properly plumbed, fully charged, securely mounted SFI- or FIA-certified onboard fire suppression system with agent-appropriate nozzles
A similar question can be asked of HANS devices. The rules require a HANS with an SFI certification. The is an expiration date on the device, but there is no rule that says it has to be "current". I sent mine in for re-cert a couple of years ago anyway:
3.B.2 Neck Brace/Helmet Support. All drivers must wear SFI 38.1-rated or FIA 8858-rated head-and-neck protection.
Unlike harnesses, which have an expiration date that is enforced:
3.F.2.a Five- or Six-Point Harnesses Mandatory. Five- or six-point harnesses mandatory, including fifth or fifth/sixth "anti-submarine" belt. All harnesses must be in excellent, near-new condition, properly mounted, and carry SFI or FIA approval tags. Harnesses with expiration dates are not valid after the expiration date.
Or is this just the question that should remain unasked.