HeyBub wrote:
wrote:
imagine a power failure in a emergency, when you really needed water
like a fire.
a ball valve 1/4 turn on main way better choice.
try to automate things too much and the equiptement may cause worse
troubles of its own
In the book, "SystemAntics," one finds the rule:
"Fail-safe systems fail by failing to fail safe."
Consider automobile brakes. Originally, you stepped on a pedal which pulled
a wire that expanded the brake shoes.
Then came hydraulic brakes. Then power-assisted brakes. Then dual-brakes.
Now anti-lock. The number of parts in the brake system has grown by two
orders of magnitude, each part with its own potential of failure.
But, in terms of catastrophic brake failures, the overall system failure
rates are lower than they were back when...
For one thing, there are many portions of those systems in that total
part count that aren't single-point failure-causing if they do fail
(anti-lock feature, for one) and in addition, some of those parts are
added redundancy (split cylinder, for example).
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