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Established: 1947

Engineer / Contractor

Previously W. LOEHLER & SON (SA) (PTY) LTD.

Dutch immigrant Christian LÖHLER, started the W. LOEHLER & SON (SA) (PTY) LTD construction company in South Africa in 1947. The name was registered in 1951. He had learnt his trade from his father, company founder Wilhelm Löhler who had started a chimney construction company in Germany in 1897 and whom he joined in 1920. They lived and worked most of their war and pre-war years in The Netherlands, building boiler installations and chimneys for many different industries, predominantly for Dutch and German farmers. Contracts in neighbouring countries were also undertaken. This included the UK as well as a contract in South America in 1907.

Shortly after arriving in Cape Town on 31 December 1947 he established himself to the best of his ability, armed with logic, common sense and a small amount of English that he learned in an American prisoner of war camp. Being fluent in Dutch, he had no problem with the Afrikaans language. The family arrived in SA in April 1948. By then he had secured a contract at White’s Cement at their Lichtenburg and Henneman operations. In 1948 the family moved to Vanderbijlpark where Christian commenced building the first of Iscor’s coke oven stacks. The company built all the Iscor (now Arcelormittal) stacks both in Vanderbijlpark and Pretoria. Christian’s oldest son Wilhelm (Willie) became involved in the business. Unfortunately he passed away due to a tragic accident in 1952.

After their studies, Christian’s sons Christiaan (Chris) and Jacobus (Jack), joined the company in 1961 and 1968 respectively. Chris took over the design and drawing office and became project engineer. Jack took charge of the administrative functions and the control of the well-trained competent staff. His structural steel background, gained while working with a well-known group of consulting engineers became very handy as well and the company was able to undertake all its own civil and structural steelwork design in-house.

In 1965 Chris established a subsidiary company called the Chimney Construction Co. One of their first contracts was the demolition of the stack of the blacksmith and foundry company George Stott that was the last remaining obstacle to the construction of the M2 east-west motorway in Johannesburg. Christian Loehler Senior originally built this chimney. Johannesburg Mayor Alec Fianski lit the fire with special matches that brought the stack down within 11 minutes. Several demolitions and new constructions followed.

In 1970 Chris and Jack became equal partners with their father, who passed away in 1981. The company finally closed its doors in 2017 after a 120-year lifespan. It is true to say that, apart from the European projects, they built the majority of industrial chimney stacks in Southern Africa. Most of these are still operational and still generate income for their respective owners and the SA Government.

The projects undertaken and completed were mainly brick and concrete stacks all over the RSA and in neighbouring countries, inter alia for the following industries:

  • Coke and coal industry – Iscor. All coke oven stacks
  • Platinum industry – JCI. Rustenburg Plats. Stacks, Pelletising plants and Butner driers
  • The Cement industry – Whites etc. Several stacks
  • The Pulp and Paper industry – SAICCOR and USUTU Pulp
  • NCP National Chemical Industries – Wadeville
  • Anglo American – Coke Oven Stacks
  • Nestle – Estcourt – Concrete Boiler stack
  • Phillips Carbon Black – Port Elizabeth. Large chimney
  • Eskom – West Bank Power Station East London, boiler stack; Taaibos and Highveld power stations
  • Otavi Mining – Bethlehem. Large Rotary Kiln installation with chimney
  • Several other Chimneys in Zimbabwe and Botswana
  • Electricity supply – Concrete stacks for Escom and Harare Power station
  • Petro-chemical industry – Sasol at Sasolburg. 150m high concrete stack
  • Most (approximately 10) of the concrete stacks for the 3 major petrol refineries in Durban and Cape Town

Other notable projects were:

Epic Oil –very large boiler installation.

Brick-making industry. Several downdraught, beehive and Hoffman kilns.

Timber industry. Numerous kilns, furnaces and incinerators etc.

The Loehler incinerators were one of the few that complied with the Department of Environmental Affairs air pollution regulations with a 99% combustion efficiency.

The company also offered a consulting service, as well as turnkey projects in most cases, which would include the design of the structures in its entirety from foundation to the top with all ancillary works such as the fire resistant lining, capping and all structural steelwork as well as the most suitable refractory lining and mortar, insulation, lightning conductor system and cast iron capping etc.

The company also operated a fully trained chimney maintenance and repair division and carried out numerous inspection and repair contracts all over the southern tip of Africa.

Chris’s father and grandfather used simple empiric rules to design and build. For brick chimneys, for instance, starting at the top with the desired internal diameter and wall thickness of one brick (9 inches/220mm) he would add half a brick every 30 feet down the stack i.e. ¼ inch per foot (6mm/300mm) thus determining the diameter at the base that would ensure a sound structure. For concrete chimneys, a taper of 58mm per every 8 feet (2,4m) of chimney height was generally used. This compensated for the cooling of the flue gases at an approximate rate of about 1°C per metre of height and thus attaining the required exit velocity rate of approx. 18m/s. This would ensure that the toxic flue waste gases would rise up into the atmosphere to the utmost possible height so as to disperse these gases over the largest possible area to minimise pollution.

Three types of stack are recognised: those that are natural based on draught, induced draught and forced draught. The first is self-explanatory, the second is where coal or oil is fired and the air required for combustion (approx.14 times as much - depending on the type of fuel being used) is drawn through the fuel by means of fans for combustion. The last is to force air into the furnace together with the fuel. The first results in a negative pressure in the chimney and the last two obviously cause a positive pressure. The problem with all these types of installations is that combustion is not always complete and that the fuel that is used is often inferior, causing a high carbon monoxide CO emission. Sulphur dioxide (SO2) is a bigger problem and when mixed with rainwater it causes sulphur trioxide (SO3) - also called acid rain - that is very corrosive.

To demolish a stack in the old days, about half of the wall was broken out at the base to a height of approximately 1 meter on the side that the stack was intended to fall to. The roof of the remaining wall was supported by timber shoring, which was then set alight. The stack then once more assumed its natural function and drew the flames through the timber struts and burned them away in about 10-15 minutes, causing the stack to fall where intended.

In the mid-seventies the company considered converting to a continuous type of concrete sliding technique and visited Germany with a view to purchase such a system to make the company more competitive in the larger stack industry by speeding up construction time. The price was rather high and was consequently abandoned. The existing system was modified and improved upon e.g. by making the raising of the shuttering and scaffolding faster by means of hydraulics. In fact, as a result of this improvement, the company established a new record by constructing 26,818 metres in 11 days. Height was never a problem but the existing system was restricted when it came to very large diameters. Price-wise the company could seldom be beaten.

Compiled by Hans Wegelin

Assisted by- Chris and Jack Lohler

March 2020