Check a row of intensity readings against your own limits, and see which fixtures to clean or re-lamp first.
Paste the intensity readings for a row of fixtures. The tool returns the minimum, maximum and average, the uniformity ratios, each fixture's deviation from the average and its percentage of design intensity, and flags the ones that fail your limits.
Add an ID before the value if you like, for example E-14 3150 or E-14, 3150. Commas inside a line separate the ID from the value, so enter one fixture per line. The values shown are sample data. Replace them with your own.
Leave empty if you only want statistics.
All limits are placeholders. Set them from your specification, the aerodrome manual or the applicable standard.
Cyan bars pass, red bars are flagged. The gold dashed line is the average and the green dotted line is the nominal intensity.
Every figure comes from the formulas below, so the result can be checked by hand.
The standard deviation is the population form, dividing by n.
The max : min ratio is shown as ∞ when the lowest reading is zero.
A fixture fails if it is below the minimum % of nominal, or if its deviation from the average is beyond the limit in either direction.
The set fails if the average is below the minimum average % of nominal, or if the max : min ratio is above its limit. A blank or zero limit is not applied.
| Item | Value |
|---|---|
| 10 readings, nominal 10,000 cd | Average 9,275 cd |
| Lowest / highest | 5,600 cd / 10,300 cd |
| Max : Min | 1.84 (limit 3) |
| E-08 deviation | −39.6 % (limit ±30 %) |
| Result | 1 flagged, E-08 |
It does not know which standard or specification applies. All limits are placeholders you set. It does not correct for meter error, aiming, ambient light or brightness step, so take every reading the same way. A pass here is not a compliance certificate.
Quick answers on checking a row of intensity readings against your own limits.
It checks a row of intensity readings against limits you enter, and shows which fixtures to clean or re-lamp first. It returns the minimum, maximum and average, the uniformity ratios, each fixture's deviation from the average and its percentage of design intensity, and it flags the fixtures that fail your limits.
Paste one fixture per line, in candelas. You can add an ID before the value, for example E-14 3150 or E-14, 3150. A comma inside a line separates the ID from the value, so each fixture must be on its own line. The values shown on the page are sample data, so replace them with your own.
It calculates the average, the standard deviation in its population form (dividing by n), and the coefficient of variation, which is the standard deviation divided by the average. The uniformity ratios are minimum to average, minimum to maximum, and maximum to minimum. The maximum to minimum ratio is shown as infinity when the lowest reading is zero.
A fixture fails if it is below the minimum percentage of nominal intensity, or if its deviation from the average is beyond the limit in either direction. The whole set fails if its average is below the minimum average percentage of nominal, or if the maximum to minimum ratio is above its limit. A blank or zero limit is not applied.
No. All limits are placeholders that you set from your specification, the aerodrome manual or the applicable standard. Limits depend on the fixture type and the circuit category, so confirm them before issuing a compliance result. The design or nominal intensity is optional, and if you leave it empty you only get the statistics.
With the sample data, ten readings against a nominal of 10,000 cd give an average of 9,275 cd, with a lowest of 5,600 cd and a highest of 10,300 cd. The maximum to minimum ratio is 1.84 against a limit of 3. Fixture E-08 deviates by minus 39.6 percent against a limit of plus or minus 30 percent, so one fixture is flagged.
Take them with a calibrated meter, under the conditions your specification requires, and at the same brightness step for every fixture. The tool does not correct for meter error, aiming, ambient light or brightness step, so each reading must be taken the same way.
No. It is an engineering reference tool, and the tool does not know which standard or specification applies. The limits entered are the user's own and shall be confirmed against the specification, aerodrome manual or applicable standard before a compliance result is issued.
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