MercTech
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Joined: 7/4/2006
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This thread is to shed some light on the lead issue and not derail another topic on another issue that sidetracked about lead in building materials.
Lead for water supply lines started to be banned by building codes in the 1930s. But, lead based solder for copper piping remained in use until the 1980s.
That is one reason one was told to never, ever, ever use the water from the hot tap for cooking. The hot water in the pipes would leach the lead from the solder joints. In cold temperatures, lead forms a pasivating layer and doesn't dissolve in the water. But, the pasivating layer will be removed by hot or acid conditions. With what I know now, I might question whether it would actually be hazardous but lead soldered hot water pipes will become detectable for dissolved lead whereas the cold water pipes will not.
Lead pipe for sewage piping was still installed in some areas until the EPA regs from 1972.
There wasn't an effective replacement for hammered lead roofing until the polymeric barrier systems first marketed in the 1990s. The tar/gravel/cement system used on many commercial buildings has its own carcinogenic hazards but a PBS roof outshines them all. (think fiberglassing the roof with the resin colored whatever you want)
Solder for piping is traditionally a lead & tin alloy. These days a more expensive lead, tin, silver allow is used to reduce the lead content. Brazing uses a silver, copper alloy and is the norm for putting in copper water pipe.
Copper piping is the best and longest lasting but much more expensive. Galvanized steel piping was extensively used in the past but degrades from the inside and plumbers no longer recommend it and many will not install it. The current state of the art is to use some version of plastic piping.
PVC (Poly Vinyl Cloride) - White in color, cheap. easy to install. Brittle with little to no flex. Degrades under ultraviolet light. Unsuitable for hot water pipe. Commonly found in cheap home water supply systems, under sink drain fixtures, irritations systems. Schedule 40 PVC may be the most common water piping today.
UMHW Piping - Grey in color. More expensive than PVC with a small amount of flex. Has a higher pressure rating for a given size than PVC. Often found in manufactured homes.
PEX - the growing standard. Flexible If you get a freeze it can expand up to 10% without damage. Did I say flexible? Read that as you can do a 12" radius bend when routing and not need joint fixtures to go around corners. Uses compression fitting piping fixtures so no cement or soldering is needed.
Any plastic pipe can be done buried. For the rigid piping, you need crush protection on your pipe channel if it runs under an area where vehicles will be driving.
The amount of lead you can get from a water pipe is really very miniscule for several reasons. But, if your kid eats paint chips of lead based paint or handles lead based paint surfaces then sticks the hands in the mouth he can get up to above 5mcg/dL in short order and even get above 30mcg/dL. (re: http://www.cdc.gov/nceh/lead/ACCLPP/blood_lead_levels.htm )
5mcg/dL is considered safe limit for children below age 5. 30mcg/dL is the point at which an adult might see some effects from lead exposure.
There are many people out there that have been exposed to so many FUDmongers (Fear Uncertainty & Doubt... a lot of people making a living selling that stuff) and believe they are going to be terminally ill if someone puts a lead brick in the same room with them. Lead paranoia may be second only to asbestos paranoia in the United States.
The paranoia over lead originated from children being brain damaged from lead exposure. The issue was never over lead pipes, tire weights, or anything metallic; it was over paint.
Lead White s lead oxide. It has been used since Roman times as a paint pigment or even as makeup. Zinc oxide supplanted lead oxide for topical skin problems but it was as effective and eating either is quite toxic. The issue actually originated with mold. Yep, mold. Mold growing on the white lead,very cheap, paint was causing the lead oxide to go airborne and people were breathing it in so huge amounts were getting into the blood stream. Lead oxide isn't all that water soluble but eaten or breathes in it will get in the blood stream when the stomach acid breaks down the lead oxide.
Lead piping and solder has been phased out not due to an issue with water pipes but from the plumbers doing the soldering and brazing breathing in the lead fumes.
The bottom line is that being around elemental lead is not going to effect your health unless you are doing something extreme. You should see the workers in a battery factory with all the lead dust flying around and they rarely show higher than 10mcg/dL. (Actual "lead workers" get frequent blood tests for serum lead to make sure they are not being overexposed)
Ok, taking my hazmat hat off and returning you to your usual topics....
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The lead pipe cinch... - 
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