I almost messed up a big apartment building floor plan because of a red/green legend

Back in the day, I'd just use red for hot water lines and green for cold on my plumbing diagrams. Thought it was obvious, right? Then about 6 months ago, my new apprentice, who's colorblind, asked me which line was which on a complex job for a 12-unit building. He couldn't tell them apart at all. That was a huge wake-up call. Now, I always use a solid line for hot and a dashed line for cold, no matter what color they are. I also label every single line with 'H' or 'C' text right on the drawing. It takes an extra 10 minutes, but it stops any mix-up. Has anyone else had a close call like that with technical drawings?

2 comments

2 Comments

the_blake1d ago

Color coding still works for most people though. A good legend at the start of the plans should cover it without needing to label every single line.

the_viola1d ago

Yikes, that's a scary story. @the_blake, a legend isn't enough if someone literally can't see the difference. It's not about what works for most, it's about making sure it works for everyone, full stop. Your fix with the solid and dashed lines is perfect. It's like how crosswalks have those bumpy tiles for blind people. The extra ten minutes saves a ton of headache later when the plumber is on site and confused. Good on you for changing it up.

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