Do BOSHART BPF and SSPF Push-Fit fittings hold up in freezing temperatures?

The water systems should never be allowed to freeze. When water freezes, ice expands by 9% in a closed plumbing system, this expansion causes pressure to increase beyond the fittings pressure rating. This increased pressure will ultimately cause the pipes and fittings to burst and fail. Fitting failures caused by freezing are not covered for warranty.