Karl,
Thank you for your response. I do know that bronze has been used for through
hulls in the past, but rarely now in steel hulls because of electrolosis
issues. Although bronze satisfies the Lloyds issue, its use brings to bear a
whole new set of corrosion issues.
Steve

"Karl Townsend" wrote in message
anews.com...

Will urine ie human waste corrode 316L valves and pipe? The question is
asked because waste tanks are typically plastic, but Lloyds A1
certification requires all through hull valves to be fire proof.
Fireproof valves are typically 316L. I have purchased all my valves from
the chemical industry. I

FWIW, there have generally been bronze valves in the head on most Ocean
charter fishing boats.

Karl