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Tolerance (AS1851)

Tolerance (AS1851)

Australian Standard AS 1815 describes how often (frequency) the routine service of fire protection systems and equipment should occur. The term tolerance was also included in the Standard to provide guidance to readers on the allowable maximum and minimum duration between the frequency of routine service activities.

AS 1851:2012 - Clause 1.11.1 General
The frequencies adopted in this Standard are set out in Table 1.11(A) and tolerances that apply to the frequency intervals are set out in Table 1.11(B). Tolerances shall be applied to the scheduled date of the initial activity. An activity that is not conducted within the tolerance period for that activity shall be reported as an out of tolerance activity within one week of the end of the tolerance period.

The introduction of a tolerence was added to the Standard to encourage the consistency of when a routine service activity should occur as well as to discourage missed routine service activities. Later the use of tolerence has been used as a a key performance indicator to manage fire services contractor performance.

AS 1851:2012 Routine Service Frequency Tolerance

Table 1.11(B) of Australian Standard AS 1851:2012 sets out the frequency tolerances applicable to the routine service activity frequencies as follows;

Table 1.11(B)
Frequency Tolerance (±)
Monthly 5 Working Days
3-Monthly 10 Working Days
6-Monthly 1 Month
Yearly 2 Months
5-Yearly 3 Months
10-Yearly 6 Months
25-Yearly 6 Months
30-Yearly 6 Months

Calculating Tolerence

The calculation of tolerence is determined from the date of the initial test, and then each subsequent routine service activity should be completed on or around the same day of each subsequent month (within the prescribed tolerence) of the initial test in the following activity date.


A routine monthly activity initially completed on the 15th of the month shall be compeleted within 5 days either side of that date, i.e. between the 10th and the 20th of the month. Each following routine service activity should then be completed on our around the 15th of each month, irrespective of the routine service activity frequency.

AS1851 Tolerence Calculation


In preparing this definition, we have drawn from various sources including Legislation, Codes, Standards and industry information, research and knowledge.  Like the english language, these definitions may subtly change from time to time. As such these definitions are provided solely on the basis that users will be responsible for making their own assessment of the definition and and are advised to verify all relevant representations, statements and information.