| Summary: | “Are South African Buildings as Safe as New Zealand Buildings?”
A person going into or using a building anywhere in the world has certain expectations as to the perceived and acceptable level of risk to life safety. There are also societal expectations and acceptability levels which are perhaps not explicitly stated. Building legislation in both New Zealand and South Africa appear to have similar goals, yet when applying the relative prescriptive document to a similar building in each country the perception is that one country has a higher level of safety over the other. Having worked for a number of years under both sets of building design regimes, the author was of the opinion that aspects of one prescriptive document has more stringent requirements than the other and that buildings in the one country thus had a higher apparent level of life safety than the other. The question was asked: How much difference is there in (fire) life safety for an occupant of a building in New Zealand compared to a building in South Africa? Is a similar building designed to a higher standard in one country as opposed to the other?
To test the author‟s hypothesis in a measured way a scoring system was required to quantify the relative level of safety. The comparison is carried out using the Fire Safety Index scoring system developed by McGhie. A spreadsheet analysis is carried out for similar building types (Building Use, Height, Fire Load and Number of Occupants) complying with each country‟s relevant acceptable solution or deemed-to-satisfy document using McGhie‟s weighted risk ranking model. Buildings are assessed across four Building Use Parameters (Purpose Group, Escape Height, Occupant Numbers and Fire Hazard Category). As the buildings assessed are very similar, the Building Use Scores are virtually identical; with some variations, for example, when occupant numbers are capped because of limitations on fire cell floor areas. The Fire Safety Features Score for each building is then assessed for the minimum requirements of the prescriptive documents across eight main category headings (Fire Barriers, Fire Alarm, Smoke Control, Building Fire Control, Emergency Power Supply, Communication System, Fire Service and Means of Escape) and a number of sub-categories. Once the attribute score is assigned and the
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weighting applied the total score is summed and a numerical rating score is achieved for each building out of a possible maximum score of 5.
As approximately 63% of commercial buildings (in NZ) are single storey and a further 28% are two-storey‟s high, the discussion of the differences in score between the two sets of buildings will primarily focus on one and two storey buildings, and the scoring is weighted to account for the relative building stock, with averaging used for the various occupant loads. The results show that for equivalent Working Purpose groups (WL), Mercantile Occupancies (CM) and Residential Occupancies (SR) the South African buildings are safer than the New Zealand buildings. Occupancies which are Crowd Activities (CL) and Sleeping Accommodation (SA) are safer in New Zealand than in South Africa. The Working Moderate fire load (WM) occupancy is rated equal for both countries.
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