Phase 1 – The Problem 

Earlier this year we were approached by a client with extensive warehousing, cold storage and fruit processing areas. These areas are all fully sprinkler protected in line with the requirements of The ASIB. The design and installation of these systems was done by another contractor over a period of years. It was done to a good standard and at first glance seems perfectly acceptable. 

The problem? When The ASIB was called to inspect the whole system and issue a clearance certificate, the entire system failed. 

The issue was that for all the multiple sprinkler systems (incorporating thousands of sprinklers) there was just one small pump. One very small pump. Along with two concrete water tanks. 

Although the “Block Plans” provided by the sprinkler contractor at the end of each installation showed the hydraulic demand of each system, at no point had they made it clear to their client that the water supply from his existing pump was in no way capable of fulfilling the required demand. This is like building a client a lake without mentioning that all there is to fill it is a garden hose. 

Phase 2 – Client’s First Considered Solution 

When the client was made aware of the problem by The ASIB, they returned to their initial contractor to request a solution. The proposed solution was a bigger pump of course. Much bigger! The pump duty shown on one Block Plan called for the pump to deliver 11,500 lit/min. (The existing pump delivers 4,500 lit/min) 

The real problem was that a bigger pump needs bigger tanks – in this case a calculated minimum capacity at intercept point would have to be 1,0150,000 litres. As the two tanks in existence had a known combined capacity of 950,000 litres, they informed the client that a third tank would need to be built to make up the extra 200,000 litres. 

A quote was duly issued for this size pump and this third tank. 

Phase 3 – A Second Opinion from Red Pipe Fire 

This is the point at which we entered the conversation – simply to give the client a second quote on the required solution stipulated above. Whilst I was happy to just quote “apples-for-apples”, the correct approach seemed to me to be to do my own due diligence first.  

I requested all the drawings and calculations the client had on the existing systems, as well as the ASIB report. I then went through them to make sure that the pump being offered by the first quote was correctly sized. To my surprise, when I did some calculations of my own, I could not find why such a high duty was required. The biggest demand duty I could get to was 9,700 lit/min. It turns out that the 11,500 lit/min shown on the block plan was a typo. 

This meant that straight off the bat we were able to reduce the size of the pump required to a more affordable solution. 

The problem of the undersized tanks still remained though. Even though the smaller pump now only required a combined effective capacity of 990,000 litres, that still left the existing tanks 40,000 litres short. Or did it? 

When I measured up the existing tanks I realised that the lowest point to which the pumps could suck before sucking air was actually half a metre above the bottom of the tanks with the current piping configuration. But if we were to fabricate new “Vortex inhibitors” that sat on the bottom of the tanks, the new effective capacity of the existing tanks could be raised to well over a million litres! 

This meant no more third tank! 

Phase 4 – The Solution 

After our investigations and calculations we were able to offer the client a second quote for a pump that met their actual requirement, and a piping solution that saved them building a third tank. All fully ASIB compliant. 

Although I never asked to see the initial quote (we will always follow ethical principles), I was informed by the client that our solution would save them several hundred thousand rand!  

We have since received the order and are now on the road to getting them an ASIB Certificate of Compliance.