POTABLE COLD WATER
Filter all the water entering the facility at sum. This was outlined in Legionnaires' Disease, Prevention & Control (1993) and first used at a medical center in 1984 in Syracuse, NY now the defacto standard. If the water supplier has difficulty maintaining the correct chlorine reserve in the facility, then install a wrap around chlorine feed system. The sum filter will trap large particulates, hopefully slime sloughed off from within the distribution piping. Is the cold water a Legionella problem? Well, some Microbiologists are of the opinion that bacteria exhibit exogenous dormancy, cold water keeps them in a "safe" state. I hold the opinion of heat induced pathogenicity. How many visitors riding on the "Maid Of The Mist" at Niagara Falls NY come down with Legionnaires' Disease (LD)? For that matter, how many visitors to the Falls come down with LD? In comparison, how many die in health care facilities from nosocomial LD? How many died at the flower show in the Netherlands after being exposed to mist from whirlpool displays?

POTABLE HOT WATER (PHW)
This is a problem area, more so due to fear, well-intentioned code and ignorance than anything else. The use of "swabbing" (a qualitative test for LB within pipe surfaces present or not?) coupled with new diagnostic and detection techniques has shed light on this avenue of LB amplification and LD proliferation. It's there, thus illness is possible and probable. Previous to LB testing and knowledge of the illness our grandparents and the retired died of the "pumonia". We NOW know how they got the illness and how to prevent it. It is an established fact that Legionella cannot survive at 140F, but code prevents health care facilities from taking that route and plumbers from "tweaking" the stat on a H/W heater. Vendors of Instantaneous H/W heaters tout the benefits for Legionella control - forgetting the necessary tempering that occurs downstream of the device. One must also consider that high temp will cook whatever enters the device, only to serve as food for the citizens of Slime City after tempering occurs. For Energy Conservation there may be merit to the heater, I am not competent in that area to debate it, however for Legionella control it is futile.

Increasing the temperature of the entire system to 140F on a monthly basis has been used successfully at two facilities known to me for quite some time with satisfactory control results, so far. No illness, no deaths attributable to LD with a raw water supply known to be prone to LB. Is this a good method? Hard to say, too many reported failures, however the correct course of action would be to alter code to allow 140F water and mandate the use of thermo pinch valves (RESOURCES CONSERVATION, INC. GREENWICH, CT06836) on faucets and shower heads. They work very well! If temperature goes above (110F?) they shut OFF and must be manually reset. These screw into the faucet like an aerator and tempering is done at point of use. As a side benefit one can unscrew them and flush the immediate 4-5 inches of plumbing with 140F water periodically if the room went unused for some time. Hyperchlorination? This phrase has many definitions I prefer to set limits and define in that manner. Since HYPOCHLOROUS ACID (HOCl) is the active killing agent obtained from bleach, would it not make sense to generate that ingredient rather than use the Hypochlorite which is substantially less effective? Care to venture a guess as to WHY recontamination is the reality when plain bleach alone is used?

2NaOH + Cl2 + HOH <====> NaOCl + NaCl + 2 HOH
Caustic Gas Water BLEACH
NaOCl + HOH + ACID (HCL) ----------> HOCl + NaCl + HOH ( pH <7.0)
BLEACH + ACID HYPOCHLOROUS ACID (HOCl)

Thus, our definition is to maintain 10 ppm free Chlorine (DPD test) while keeping the pH within 5-6 via the addition of acid, any acid, for 24 hours. A bit "touchy" for the maintenance worker, but should be within the capabilities of any competent water treatment professional with HVAC experience or a master plumber. The professional should be prepared for the foam, lots of foam, that will be generated as the organic slime is oxidized and lots of carbon dioxide is generated. This could be a job for a plumber on house left unattended for the winter while the occupants went South or North, depending on where one lives on the globe. Continuous chlorination of the PHW will reduce pipe longevity considerably. Copper/Silver? Raving testimonials and papers on proprietary systems would make one believe this is the route to take. However, one is never shown the failures or they are brushed aside like so much meaningless disinformation.

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