An evaluation of the primary South African standard and guideline for the provision of water for firefighting

Abstract

In South Africa, as is mostly the norm globally, national legislation and guidelines specify that potable water distribution networks maintain the capacity to provide specified quantities of water for firefighting. This paper addresses the question: is the South African standard and guideline pertaining to fire-flow provision appropriate for firefighting and do these ensure the most efficient balance between providing sufficient fire protection and promoting sustainable water use? In answering this question, this study: (i) reviewed national and international design standards and guidelines; and (ii) captured and analysed 10 years of billable fire incident reports representing 3 859 fire events within the City of Johannesburg. Highlights from the study include: inconsistencies in categories when comparing the SANS 10090 and The Red Book fire tables and violations (in The Red Book) of stipulated Minimum Fire Flows; over the 10 year period, 75% of fire incidents within the City of Johannesburg were extinguished using less than 6.6 kL of water – less than the capacity (6.9 kL) of the City’s conventional pumping tanker during the period; 99.9% of fire incidents within the City were quenched using an average fire flow rate of less than 1 200 L/min, which is the minimum hydrant flow rate for the lowest fire risk category in SANS 10090; and peak fire occurrence did not correspond with typical peak residential water use. Recommendations are proffered in respect of the above.

Water Supply and Firefighting: Early Lessons from the 2023 Maui Fires

“…Gibson et al [37] noted that North American minimum fire flow requirements for public water systems, around 1900 L/min, are about four times larger than European standards, around 500 L/min, with little defensible basis. Mac Bean and Ilemobade [38] concluded that of almost 4000 fires in South Africa, only 3 needed more than the minimum flow rate of 1200 L/min; in New Zealand, Davis [39] concluded that "a very large proportion of fires are extinguished with less than 10 L/s (600 L/min) of water". In addition to showing that smaller fire flows are generally effective, these sources agree that the most excessive fire flows are likely associated with situations where the buildings would have been lost anyway, regardless of how much water was available.…”

Water for firefighting: A comparative study across several cities

“…This was achieved because fire fighters transported water from the fire station using pre-filled tanker vehicles as the first line of defence in all cases when attending to a fire call. Mac Bean and Ilemobade (2019) [6] analyzed about 10 years (from 01 January 2006 to 30 September 2017) of fire incident reports (3 859 records) that occurred within the CoJ. Highlights from their study were: (i) the fire flows and fire risk categories in the South African National Standard, SANS 10090 (SABS, 2018) [7] and The South African National Guideline (The Red Book; [1]) are inconsistent; (ii) The Red Book recommends fire flows that are lower than the SANS 10090 and thus, violates the SANS 10090, which is a standard that stipulates minimum acceptable values; (iii) over the study's 10-year period, 75 % of fire incidents within the CoJ were extinguished using 6.60 kℓ of water or less, 87 % of fires were extinguished using 10 kℓ of water or less and 99 % of fires were extinguished using 100 kℓ of water or less; (iv) while the frequency of fire occurrence was strongly related to climatic conditions, the volume of water used to quench fires was not a function of climatic conditions; (v) over the study's 10-year period, 99.90 % and 99.60 % of fire incidents were extinguished using average fire flows that were less than the minimum fire flows for the lowest risk categories in the SANS 10090 and The Red Book respectively; (vi) The start times of peak fires did not coincide with typical peak residential water demand periods.…”

“…Essack and Ilemobade (2022) [8], using similar but better representative criteria, re-analyzed the initial database employed by [6], and in particular, addressed 89 large fires (fires requiring more than 5 kℓ to extinguish). Highlights from their study were: (i) in the initial dataset of 4 479 records (spanning 24 February 2003 to 26 September 2017), an average of 32 incidents occurred per 30day month with an expected increase in the average number of fire incidents during SA's dry and cold (i.e.…”

“…It is obvious that the average volume of water employed to extinguish fires are not correlated to the season of the year. In addition, in all studies, a significant percentage of fires (93.3% in the SPM [9], 75% in the CoJ [6], 91.4% in the 5 WC towns [5]) were (and could be solely) extinguished using certain fire engines -the Boom Pumper fire engine in the CoJ, for example, has a tank capacity of 9 kl.…”

“…Figure 4 shows that in 3 (at the CoJ [6], [8] and SPM [9]) of the 4 studies, the frequency of fire incidents increases and peaks during the dry months (April/May to September) and is the lowest during the rainy periods (December to March). In the WC [4], the rainy months are between March and November and this explains why the chart for the WC displays marginally lower frequencies between March to October when compared with frequencies at other times of the year.…”