Measurements
This chapter defines how each effect is measured. Thresholds for lowercase and uppercase letters are in Effect Letters.
- Every applicable measurement shall be taken at each group’s baseline and after each level or step.
- An effect that does not apply to a unit (for example, closure gap on a slab phone) shall be recorded as N/A.
Methods
| Effect (letter) | How to measure | Applies to |
|---|---|---|
Closure gap (c) | Insert a feeler gauge gently, without forcing, at three points along the free edge. Record the largest | Hinged or closing devices |
Hold force (h) | Tape a string loop to the centre of the free edge. Pull perpendicular with the luggage scale or gauge until it opens. Record the average of the peak readings of 3 pulls | Devices with magnets, detents or latches |
Rough motion (r) | Record audio and video of 10 cycles from 30 cm, in a quiet room. Note anything heard or felt | Devices with moving parts |
Buttons and ports (b) | Press each button or key 5 times and check that every press registers. Insert a plug into each port | All |
Screen (s) | Display full-screen white, mid-grey and black. Photograph at 0° and 45° under the same lighting. Draw a grid in a drawing app to check touch | Devices with displays |
Ingress (i) | Inspect inside ports, grilles, holes and gaps with a flashlight (UV light if a tracer was used). Record only medium or water below the outer surface | All |
Enclosure breach or electrical fault (E) | Watch for electrical faults during exposure and at each measurement. Breaches: lab teardown (see Test Tiers) | D, G, W |
Fogging (f) | [TBD] | W |
Audio (m) | [TBD], after the drying period [TBD] | W |
| Wear condition | [TBD] (see U: Usage) | Lab units |
Judgement calls
The b, r and s thresholds depend partly on the tester’s judgement.
- The baseline and per-level or per-step photos, audio and video for these effects shall be kept with the report, so others can review each call.
- Each call should be confirmed by a second person where one is available. The report shall state whether it was.
- For
r, the tester may compare the sound level of each recording with the baseline recording using a sound-level meter app. An objectiverthreshold is [TBD].