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Effect Letters

  1. Testers shall use only the letters in this list.
  2. A lowercase letter means the effect was observed and is within tolerance.
  3. An uppercase letter means the effect caused failure.
  4. The thresholds apply to every group the letter is listed for.

How letters are placed in a code is defined in Code Format. How each effect is measured is defined in Measurements.

Closed list

LetterEffectGroupsLowercase threshold (within tolerance)Uppercase threshold (failure)
b / BButtons, keys or ports impairedAllStiff or gritty; plug meets resistanceDoes not register; plug cannot seat
c / CClosure gapAllIncrease of more than 0.3 mm over baselineIncrease of more than 1.0 mm, or will not stay closed
EEnclosure breach (dust or liquid inside a sealed compartment) or electrical faultD, G, Wn/a (no lowercase form)Electrical fault (reboots, charging failure, sensor errors). A breach found at lab teardown is recorded in the report, not the code (see attribution)
f / FFogging or condensation inside a lens or displayW[TBD][TBD]
h / HHold or closing force changed (magnets, detents, latches)AllChange of more than 15% from baselineChange of more than 40%, or no hold
iIngress only, no measurable effectD, G, WMedium or water visible inside an opening, below the outer surface, with no other effectn/a (no uppercase form)
m / MAudio impaired after the drying period [TBD]W[TBD][TBD]
r / RRough motion: grinding or crunching during movementAllGrinding or crunching heard at 30 cm or feltMoving part binds: cannot complete its full range with normal hand force
s / SScreen marks, pressure points, dead pixels or touch faultsAllMarks or pressure points visible on grey at 45°Dead pixels, lines, cracks, or touch dead zones

Note (informative): All thresholds are provisional and will be adjusted once real devices have been tested. See Open Issues.

Note (informative): Medium resting on the outer surface or in the outer lip of a seam is not ingress. Sprinkled medium always lands there, so counting it would put i on nearly every test.

Note (informative): Rough motion uses r rather than g because an uppercase G would collide with the G group letter.