It seems better to start a separate thread about the various issues addressed by the AAMI A3 proposed changes.

Section E.3.2 Backflow Prevention: The proposed standard says a backflow device such as a PPBA or a vacuum breaker should be installed. It mentions local codes requiring specific types.

Why a portable RO system is considered a serious risk to contaminating a hospital domestic water supply is beyond me. A hospital has other equipment connected to the water supply like boilers with toxic chemicals added, and chiller systems with toxic antifreeze chemicals, that are serious risks. The only real risk from a portable RO is if the reject water discharge is submerged in a toilet or sink.

The “safest” backflow prevention device is the reduced pressure zone (RPZ) backflow preventer. The proposed standard for some reason calls this a pressure principle backflow assembly (PPBA). Whatever, they are heavy, bulky, leaky, expensive and typically impose about a 10 PSI pressure drop. They are supposed to be tested yearly by a professional.

A vacuum breaker is listed as an acceptable alternative device. I agree. It leaks when connected or disconnected, but otherwise is small, cheap, simple, and does not cause pressure drop. If part of a sink faucet fitting, any leaking will go into the sink.

Typically only the incoming water pressure is available to overcome pressure drops through prefilters, carbon filters, softener, etc. before the water enters the high pressure RO pump. So the pressure drop of a RPZ device can prevent or hinder operation of a portable RO. A booster pump could be added, but makes the unit less portable.

The standard says a local plumbing code might require a break tank, which is even more cumbersome than a RPZ device.

I think the AAMI code should instead state that its requirements should supercede those of local plumbing codes in regards to portable water systems for dialysis.

quote:

I think the AAMI code should instead state that its requirements should supercede those of local plumbing codes in regards to portable water systems for dialysis.

I don't know but it seems to me that AAMI would have no say in local or state requirements for plumbing. Just like they have no say in the National Electrical Code.

I'd like a simple statment of, "Follow local codes.", but our local codes require RPZ or breaktank-no third option. A portable RO with an RPZ mounted on top, then with a booster pump mounted inside beomes a top-heavy, unstable, nurse chucker.