Plumbing Size Fun

I was brain-dead on “Thursday”: My neighbour helpfully pointed out that I can replace the cracked copper DWV piping with ABS; they make ABS < -> copper fittings for this purpose. No plumber required; even _I_ can work with ABS :-)

So I need to run out to the store and get a bunch of ABS piping, and adapters. However, I need to know what size to get. Applying my superior mathematics skills, I measure the outside diameter of the pipe at slightly less that 10″. Divide by pi, and the pipe diameter is slightly less than 3.18″. Now, I _know_ that copper pipe is made in 3″ and 3.5″ sizes, not 3.18″ :-). This could be an inside diameter vs. outside diameter thing, but the number is still strange. Still, it’s probably safe to assume 3″, right?

Fortunately, there is google. The third hit for “copper pipe diameter”: is “Notes on Pipe”:, which explains that:

bq. Oddly, there is nothing about a ½” pipe that is ½”, be it copper, iron, or PVC

bq. Well, it seems that back in the beginning of time – copper pipe was introduced in the 1930’s – copper pipe was indeed standardized at the nominal diameter inside with a 1/16″ wall, making it 1/8″ bigger on the outside. As the metallurgy improved, allowing manufacturers to use thinner metal (and thus increase profits), they increased the inner diameter rather than decrease the outer diameter simply to allow the pipe fit existing fittings.

bq. As the manufacturers began to make bigger and bigger pipe, they found that 1/16″ wall thickness was insufficient. Thus, the inner diameter of larger pipes is smaller than the nominal size, while smaller pipes are larger.

And, usefully, a chart of nominal sizes with actual measurements, telling me that my assumption is correct; my 3.18″ pipe is, in fact, a 3″ copper pipe!

Next week, we learn why 2″x4″ lumber is neither 2″ nor 4″ :-)

posted at 12:20 pm on Sunday, July 04, 2004 in Personal | Comments Off on Plumbing Size Fun

Plumbing Trouble and Bird Nests

So I found the moldy smell.

The downstairs bathroom has been smelling moldy, for a little while, but between the funeral and our camping trip, I haven’t had time to deal with it. Yesterday, I finally started investigating. The odour was coming in through the vent fan, sucked in by the chimney effect from the upstairs skylight.

The previous owners had blocked up the outside portion of the vent pipe; I was hoping that the problem was that water was getting in from the outside, and soaking the insulation they had stuffed into the pipe.

Unfortunately, that wasn’t it.

I discovered that the vent pipe wasn’t actually connected to the fan; there was an eight inch gap into the empty space between the ceiling and the upstairs floor. Looking closely, I saw the telltale signs of a nail starting to pull out of wet drywall (which wasn’t there before; the problem has apparently been getting worse)…

So I started pulling the ceiling apart. Imagine my surprise when I found that the layer above the drywall was twigs, leaves, and shredded newspaper!!! The reason the previous owners had blocked the vent pipe was that birds were getting in. Sadly, they left the nest in the ceiling; Eight inches deep, and about 3′ square. That much humus can hold a lot of water, and when it gets wet, it rots. Tah-dah; instant mold.

I pulled two garbage bags full of stuff out of the ceiling before I ran out of wet. After cleaning up, I was able to explore the space. Immediately above the wet spot is the upstairs toilet. After wiping off the dampness, I saw the leak; a roughly 1mm crack, in the pipe itself, next to an elbow joint. Such a small hole, to cause so much trouble…

I don’t have the equipment (or skills) for such a repair; time to call the plumber!

posted at 3:23 pm on Friday, July 02, 2004 in Personal | Comments Off on Plumbing Trouble and Bird Nests

Health News

* “Black Tea May Help Get Blood Circulating”:

bq. The authors suspect that black tea improved the dilation of the men’s blood vessel, allowing better blood flow [to the heart].

* “Atkins-style diet could damage chances of having a baby”:

bq. The research — conducted on mice — found that a diet containing 25 percent protein disrupted the normal genetic imprinting pattern in early embryos. It also had an impact on embryos that were transferred to other uteruses.

bq. Embryos receive copies of most genes from both parents, and imprinting causes a gene from just one parent — and not the other — to be switched on. If both gene sets are switched on, development can go haywire. Imprinting flaws are widely blamed for foetal malformations and the extremely high rate of spontaneous abortions among cloned farm animals.

* “Watching TV may speed up puberty”:

bq. Watching too much television may distort the hormonal balance of adolescents and push many of them into early puberty, say researchers. Italian researchers found children denied access to television for just one week experienced a 30% jump in their melatonin levels. The hormone is thought to prevent the early onset of puberty.

(All via “Teal Sunglasses”:, apparently my best source of filtered health news :-)

posted at 10:09 am on Thursday, July 01, 2004 in Health | Comments Off on Health News
« Previous Page