NOTE: Make sure you read the first three posts (in order!) before tackling the rest, or it could be confusing: Post 1 is Designing the future, Post 2 is Setting up the problem, and Post 3 is Estimating basic requirements.


Tuesday, September 05, 2006

Calling the Maintenance Man

There are a number of practical considerations you should keep in mind early in the design process, which fall under the “-ilities” category – things such as maintainability, reliability, availability, and producibility. These characteristics of your system/community describe the practicality of building, using, fixing, and upgrading your project. I’ll talk about each one in turn, but for this post I’ll focus on maintainability.

Easy-to-maintain systems are especially critical for a post-Peak Oil community. If a pipe bursts, is there a plumber who can fix it? If your electric refrigerator fails, who can fix it? What parts will you use to fix it? How long will it take to fix? When specialists, available replacements, and time are scarce, the capability for quick and easy fixes is critical.

There are a few guidelines that will help you design maintainability into your system at all levels:

1) Replacement parts – Plan for acquiring and storing replacement parts for each of your systems, OR provide a method for fabricating replacement parts using materials on hand. You can be efficient about this – figure out which parts of your system will have a higher failure rate (e.g. valves or light bulbs) than others (e.g. pipe or wires) and plan accordingly. Ideally, you should have a plan for fabricating all replacement parts over the long-term, or accept that some parts of your system will eventually fail – oil scarcity = parts scarcity.

2) Modularity – Keep your interfaces simple so that replacement of a single component can happen quickly. For example, suppose you need to replant a portion of your green roof – if you designed your roof as a collection of modular containers, you can swap one out for a fresh one rather than spending all day replanting on a sloped surface.

3) Test points/Break points – Allow for trouble-shooting, especially in complex systems. Think of the circuit breakers in your house: they work to isolate a portion of your home electrical system and help you narrow down the source of problems.

4) Consistency – Try to use the same parts wherever possible. Rather than having one kind of faucet in the kitchen and another kind in the bathroom, consider using the same model. This will make your replacement parts a little easier to manage and limit the amount of information you have to remember about different types of components.


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