The difference between PVC and CPVC pipe.

I decided to undertake a little plumbing project here at my office this week, and unsurprisingly, there were opportunities for mental growth (and some chemically destroyed brain cells) encountered along the way.

As you can see, the project was to transplant a small water heater from a building where it was no longer in use, into our office.  We haven’t had heated water here since renovating and repurposing ‘this old house’ into our office space in 2006.  We haven’t really missed it too much, but with the shorter days of winter, I’ve been itching to move my workouts to the early morning to help me get my days started with a little more energy.  Having a place to shower up and change into work attire here at the office would be a big help in bringing that ‘itch’ to a reality.

So, after studying the network of existing iron pipe, I determined a suitable location for an emergency drain pan, and set about acquiring all the fittings and pipe needed to plumb the new water lines.  I had always heard that CPVC was more appropriate for hot water applications, but didn’t really know what the difference was.  Never being satisified with, “because that’s what CODE requires” as an answer – I set about getting the technical and practical answers to my questions:

A technical explanation of the differences that make CPVC special:

CPVC is PVC (polyvinyl chloride) that has been chlorinated via a free radical chlorination reaction. This reaction is typically initiated by application of thermal or UV energy utilizing various approaches. In the process, chlorine gas is decomposed into free radical chlorine which is then reacted with PVC in a post-production step, essentially replacing a portion of the hydrogen in the PVC with chlorine.

Depending on the method, a varying amount of chlorine is introduced into the polymer allowing for a measured way to fine tune the final properties. The chlorine content may vary from manufacturer to manufacturer; the base can be as low as PVC 56.7% to as high as 74% by mass, although most commercial resins have chlorine content from 63% to 69%.^{[citation needed]} As the chlorine content in CPVC is increased, its glass transition temperature (T_g) increases significantly. Under normal operating conditions, CPVC becomes unstable at 70% mass of chlorine.

Various additives are also introduced into the resin in order to make the material processable. These additives may consist of stabilizers, impact modifiers, pigments and lubricants.

And a more practical explanation of why it’s required in hot water applications, and how it got it’s goofy sizing and color:

In the case of PVC, when it was first introduced into the plumbing trade in the mid 60’s it was approved for all potable water systems, both supply and distribution. At that time it was also a common practice to operate water heaters at or near 180degF.

It was soon discovered that PVC will exhibit wall softening and glue joint failures at temperatures approaching 150degF, which explains why the ASTM standard for PVC now limits it to applications not exceeding 140degF. )

The PVC formula was then improved upon to create CPVC which can withstand temps up to 190DegF for a short time.

Initially the codes were ammended permitting PVC in the cold water service, but requiring CPVC in all “Hot Water” applications, however this lead to a lot of confusion amongst the general public and it was soon discovered that homeowners and DIY’ers were erroneously using the PVC in applications that required CPVC. It must also be noted that initially CPVC was made in the same white color and to the same Sched.40 dimensional specifications as was the PVC which then lead to a lot of confusion by mixing both the pipe and fittings. CPVC is still made to sched.40 specs and the only method of distinguishing the two materials is to actually read the labelling printed on the pipe wall.

The CPVC that is commonly used for distribution piping today is not made to ASTM pipe Schedule standards, but rather it is CPVC-CTS, (Copper Tube Standard) which explains the difference in overall tube dimension.

Something to keep in mind the next time you’re futzing around up in your attic, playing with the sawzall and sucking pipe glue fumes…

That posting to this blog on a daily basis was unrealistic.

No matter how well intentioned it was, making the point of this blog to post in detail about something new EVERY single day was not something I could keep up with.  I still believe that I do learn something new each and every single day, I just don’t always have time to break it down and post about it.

 

Maybe if I just put something up every now and then, that would still serve some useful purpose in the world?

 

I guess we’ll find out!

That the 6th largest pyramid in the world is in Memphis.

While watching The Firm with roommates tonight, I spotted the pyramid arena in downtown Memphis, and it struck me that I didn’t know a damned thing about it.  I actually thought for a minute it was a goof, and that a shot from the vegas desert showing the luxor had been put in the movie…

To Wikipedia:

The Pyramid Arena is a 20,142-seat arena located in downtown Memphis at the banks of the Mississippi River. The facility was built in 1991 and was originally owned and operated jointly by the city of Memphis and Shelby County. Its unique structure plays on the city’s namesake in Egypt, known for its ancient pyramids. It is 321 feet (98m, about 32 stories) tall and has base sides of 591 ft; it is the sixth largest pyramid in the world behind the Great Pyramid of Giza (456 ft), Khafre’s Pyramid (448 ft), Luxor Hotel (348 ft), the Red Pyramid (341 ft) and the Bent Pyramid (332 ft), both in Dahshur. It is also slightly (about 16 feet) taller than the Statue of Liberty. A statue of Ramesses the Great stands in front of the pyramid.

It further turns out that the thing has been a colossal economic failure, and is currently expected to be redeveloped into the world’s largest Bass Pro Shops.  Seriously:

In October 2005, media speculation began to focus on an aquarium or a Bass Pro Shops superstore as the most likely long-term tenants of the arena. In 2008, the city and Bass Pro Shops reached a “tentative” agreement, short on details, but based on an intent to develop the now-abandoned structure.^[4] On June 30, after 5 years of negotiating, Bass Pro and the City of Memphis signed an agreement for a 55-year lease which would create the main store, additional retail stores, restaurants, offices, and a river museum. In addition, the redevelopment plans include revitalizing the Pinch District, which is the neighborhood around the Pyramid. The city would invest 30 million dollars to help with the seismic retrofitting of the structure, all of which would be funded by future sales tax revenue in the surrounding area. Therefore, essentially no taxpayer money will be spent on this project. Bass Pro hopes to open its store by November 2011. ^[5]

FAIL!

That you can forget how to ride a bike.

Or, more specifically that you might forget how to bust out of your clipless pedals when you come to an obstacle that you either can’t or don’t want to pass without your feet on the ground.

No guides, references, or cute illustrations here – just one tip:  lean towards the high side of the trail!

When it’s appropriate to use your’s.

Aparently NEVER.

Oddly, I had to find this out while I was trying to figure out how to give the plural form of the possessive.  I thought yours’ might be appropriate, but it turns out that yours is always the way to go…

Google provides us with this article:

Your’s

Though you may see your’s written even by native speakers, it is incorrect. Yours should never have an apostrophe.

How to reverse the drive on a 1/2hp split-phase 240v motor.

So, it turns out that one of the exhaust fans on a building of ours was re-installed incorrectly after our construction/addition to the building.  It was turning counter-clockwise, which would be great, except that the blades were setup for clockwise rotation, and that means the fan would do nothing except immediately suck the louvers shut and spin with no real effect.

I crawled up a ladder with a meter, camera, and screwdriver – expecting to find 2, or maybe 3 wires which I would then piddle with until the motor changed directions.

WRONG.  What I found behind the cover on the motor was this:

Looks a little daunting, no?

To the internet (specifically wikipedia) for more guidance:

Split-phase induction motor

Another common single-phase AC motor is the split-phase induction motor,^[5] commonly used in major appliances such as washing machines and clothes dryers. Compared to the shaded pole motor, these motors can generally provide much greater starting torque by using a special startup winding in conjunction with a centrifugal switch.

In the split-phase motor, the startup winding is designed with a higher resistance than the running winding. This creates an LR circuit which slightly shifts the phase of the current in the startup winding. When the motor is starting, the startup winding is connected to the power source via a set of spring-loaded contacts pressed upon by the stationary centrifugal switch. The starting winding is wound with fewer turns of smaller wire than the main winding, so it has a lower inductance (L) and higher resistance (R). The lower L/R ratio creates a small phase shift, not more than about 30 degrees, between the flux due to the main winding and the flux of the starting winding. The starting direction of rotation may be reversed simply by exchanging the connections of the startup winding relative to the running winding.

The phase of the magnetic field in this startup winding is shifted from the phase of the mains power, allowing the creation of a moving magnetic field which starts the motor. Once the motor reaches near design operating speed, the centrifugal switch activates, opening the contacts and disconnecting the startup winding from the power source. The motor then operates solely on the running winding. The starting winding must be disconnected since it would increase the losses in the motor.

Huh?

OK, sometimes I over think things, maybe I should have looked at the label on the motor first.  They have to make these things simple enough for a shop monkey to understand.  Notice the bit I circled in photoshop:

Wires reversed, motor turning clockwise, heat being exhausted, lesson learned.  Although I feel like I probably cheated myself out of a real lesson in electrical engineering by not diagramming the motor windings and starting capacitor circuit…

A new word: “grouser”.

While visiting a job at one of our sand pits, we were looking at the hydraulic excavator (often mistakenly called a backhoe) being used on the job, which was an unusually large Caterpillar 330D:

When my dad mentioned that you could tell it was a big machine just by looking at the grousers.  I’m pretty sure that nobody else in car knew what he was talking about, but I was the only one willing to ask for an explanation.  What he rattled off, was pretty close the following from wikipedia:

A grouser or cleat is a protrusion on the surface of a wheel or continuous track segment, intended to increase traction in soil, snow, or other loose material, in the same manner as cleated shoes provide traction to athletes. Track segments which incorporate grouser bars are known as grouser shoes, and typically include one to three grousers.^[1] Grousers are commonly used on construction vehicles such as bulldozers, loaders, and excavators, as well as tanks, agricultural vehicles, and snowmobiles.

For anyone who has WAY too much time on their hands, I recommend you read the entire article, which includes a section on Terramechanics, with a formula for calculating “gross tractive effort, or soil thrust“:

I’m not sure when I’ll put those pieces of knowledge to use, but then I never really am…

What speed-dating is actually like.

So, I saw a Groupon the other day for half-price speed-dating, and I already had a $5 off your next Groupon purchase code.  This made it an $8 ticket to experience firsthand one of those things you really only ever see in movies.  I thought to myself – what are the best and worst case scenarios?  Best case: I meet someone or several someones who are interesting and attractive.  Worst case: I meet a bunch of closet cases and have a fun story to tell later.

So how does it work?

How Dating Parties Speed Dating Events Work

1. You search for your city and find the event that matches your preference. If you do not see your city or an event that matches your preference contact us and we will plan an event that fits your needs.
2. All Speed Dating Events will be titled with “Speed Dating”.
3. Once you have found the event you want to attend there are two easy ways to register. First is on the website, all you have to do is fill out our Registration Form and Create an Account . This is easy and all we need is some basic contact information. Then follow the on screen instructions and you are registered for that event in no time! You will receive a confirmation E mail giving you all the details about the event you just registered for. Also by registering this enters you into our weekly Email newsletter which keeps you up-to-date on all of our future events in your city. Or you can register by phone at 1-866-333-0282.
4. You MUST be pre-registered before the event begins, there will be no-site registrations. We do this to keep the events as evenly balanced as possible.
5. You then show up to the event about 5-10 minutes EARLY to sign-in with the Party Coordinator, you will receive your name badge, personal Dating Card and your seating assignment.
6. You go on your 7 minute “mini dates” and meet 8-12 (and sometimes up to 15) other professional singles in less than 2 hours at a local upscale venue usually in the establishments private or sectioned off room. We organize everything so you are guaranteed to meet everyone there and have a fun and safe time. Many of our events include free appetizers and/or drink specials.
7. We supply you with your own personal Dating Card for you to keep track of all the people you will meet, where you can write down your own private personal notes about each of the individuals and decide whether you would like to see them again. It’s a simple “Yes or No”.
8. After the event is over you take your personal Dating Card home with you and the next day log – in to this website and enter and view your matches.
9. If there is a mutual match you will receive their Email address just as they will receive yours. Since there is a connection already made you are on your way to creating a lasting connection with that individual.

So, how does it REALLY WORK?  In practice, things weren’t nearly as awkward as I assumed.  Everyone seems to realize that this is supposed to be fun, and that there’s almost no chance you’re going to really get to know someone in 5 minutes.  So, you just focus on enjoying the conversation, and making the other person feel at ease.  Honestly, speed-dating would make good therapy for agoraphobes, and the dysfunctionally shy.  It’s kind of neat to run around from station to station with your scorecard (think putt-putt) making notes about people too.

For myself, I think maybe speed-dating is a little to far towards the desperate end of the scale.  I met some nice people while I was circulating around, but because I’m a little picky about personality, geography, etc I really only felt like 1 or 2 of the people at the event were “my speed”.  I guess if I didn’t have a social structure and/or the ability to meet new people on my own I could tough out speed-dating 2 or 3 times a month until it bore fruit.

Just goes to show you that there are 100 different ways to skin a cat…

How my brakes broke.

So, you’re riding along on a beautiful Sunday afternoon, exploring a new trail, and as you prepare to make your way down one of the first of many exciting chutes you reach for the rear brake to wipe a little speed off before the descent.  Surprisingly, actually shockingly, the lever bottoms out into the handlebar, as if to say, “Grow some balls, and hit that thing at full stride!”  Well thanks for the suggestion, Hayes HFX-9 Hydraulic Disc Brake, but I think I’ll limp back to the truck and live to play again next weekend…

So, what went wrong?

Well, for starters, I probably should have acknowledged that there is no such thing as a “little leak” when you’re talking about a hydraulic disc brake setup.  The paint fading away on the lever probably should have clued me in that the acetone based brake fluid was going somewhere other than the stoppy bits…

But, that didn’t really satisfy my curiosity as to what happened in there to let the “stop’em goo” out into the world.  So, to the exploded view diagram we go:

After taking the whole mess apart, cleaning it up, and studying the diagram – I’m pretty sure that the push rod (#34) started to rust from environmental factors (not to mention the fact that they’ve got steel touching aluminum, which is always a design no-no.  Once the rod was worn unevenly, it took the retaining washer (#35) with it.

No problem you say?  Just buy a rebuild kit for some reasonable price and move along…

WRONG.

Try $120 for the only available parts I could find, which weren’t really certain to be right for my model anyway.  Now price that against $135 for front & rear replacements that look like:

Easy Decision.  In 2-3 business days, plus wrench time to install, look for me at the top of one of those chutes, clutching my new Carbon Fiber Brake Levers!

About the differences between “open source” and “free”.

One of the things I’ve really enjoyed about having a phone with the Android OS from Google is seeing the power of open source to enable a community to form around a platform.  If I can think of something I wish my phone did or didn’t do, you can bet there are other (smarter, more ambitious, more capable, and less busy) people out there thinking the same thing.  Recently however, Google has decided to withhold the release of code for their most recent software version, Android 3.0 – Honeycomb, which is pointed squarely at tablet devices (like my Barnes & Noble Nook Color). 

Their reasoning is understandable, but it doesn’t change the fact that a community doesn’t like being told what to do by its benevolent benefactor…

From the Android Developer’s Blog, on April 6, 2011:

[This post is by Andy Rubin, VP of Engineering —Tim Bray]

Recently, there’s been a lot of misinformation in the press about Android and Google’s role in supporting the ecosystem. I’m writing in the spirit of transparency and in an attempt to set the record straight. The Android community has grown tremendously since the launch of the first Android device in October 2008, but throughout we’ve remained committed to fostering the development of an open platform for the mobile industry and beyond.

We don’t believe in a “one size fits all” solution. The Android platform has already spurred the development of hundreds of different types of devices – many of which were not originally contemplated when the platform was first created. What amazes me is that even though the quantity and breadth of Android products being built has grown tremendously, it’s clear that quality and consistency continue to be top priorities. Miraculously, we are seeing the platform take on new use cases, features and form factors as it’s being introduced in new categories and regions while still remaining consistent and compatible for third party applications.

As always, device makers are free to modify Android to customize any range of features for Android devices. This enables device makers to support the unique and differentiating functionality of their products. If someone wishes to market a device as Android-compatible or include Google applications on the device, we do require the device to conform with some basic compatibility requirements. (After all, it would not be realistic to expect Google applications – or any applications for that matter – to operate flawlessly across incompatible devices). Our “anti-fragmentation” program has been in place since Android 1.0 and remains a priority for us to provide a great user experience for consumers and a consistent platform for developers. In fact, all of the founding members of the Open Handset Alliance agreed not to fragment Android when we first announced it in 2007. Our approach remains unchanged: there are no lock-downs or restrictions against customizing UIs. There are not, and never have been, any efforts to standardize the platform on any single chipset architecture.

Finally, we continue to be an open source platform and will continue releasing source code when it is ready. As I write this the Android team is still hard at work to bring all the new Honeycomb features to phones. As soon as this work is completed, we’ll publish the code. This temporary delay does not represent a change in strategy. We remain firmly committed to providing Android as an open source platform across many device types.

The volume and variety of Android devices in the market continues to exceed even our most optimistic expectations. We will continue to work toward an open and healthy ecosystem because we truly believe this is best for the industry and best for consumers.

We shall see what comes next.