EBME Forums Forums Maintenance Test Equipment Testing Patient Scales

With reference to the attachment you provide, I have no idea what E2, F1 et al mean.

But for purposes of discussion, here are a few more documents (hopefully they are still in current use):-

1) NAWI
2) LACORS
3) NMRO
4) GOV.UK

When it comes to allowable tolerances, I prefer to think about ± percentages. Taking a quick look at a randomly selected patient weighing scale (actually a Seca Model 769); it claimed an "accuracy" of "greater than ± 0.15 %".

In the NAWI document the "in-service allowance" for a 0-200 kg Class III gives an allowance of ± 200 g. I make that to be ± 0.2 % when weighing a 100 kg load (patient).

I take three points from that brief exercise:-

1) The scales have a greater accuracy than the "spec"
2) Modern electronic scales are very accurate
3) 200 g of water relates to 200 ml

Surely any "shade-tree biomed" techniques we use when checking weighing scales with water-filled containers can attain at least as good as ± four 50 ml syringes worth of volume!

Hopefully someone will check my workings here.