MechChem Africa

MechChem Africa columnist, Gary i Crawford of Mettle Strategic Creativity, is currently building a new property in Hartbeespoort using only light steel frame construction principles and products. Here he presents some of the innovative products available for those seeking to go beyond the traditional.

The construction industry is inefficient and slow to innovate. At least that's the impression of many people, including me, who feel that the comfort zone of currently used materials and techniques is too comfortable to risk the downside of trying something new.

I make no claim for any of the products mentioned in this column, save to say that some have been included in my current build – with no strings attached. And I intend, in the near future, to publish a case study on the experience, following the completion of House Crawford, Hartbeespoort.

Gary i CrawfordGary i Crawford, who is building an LSF home using modern materials and construction techniques.

Corrugated stainless steel pipe: Available in some other countries since the 1980s, corrugated stainless steel pipe (CSSP) is now manufactured in South Africa by INOX. CSSP is suitable for most water distribution in residential, commercial and industrial applications. Manufactured from corrosion-resistant 304L and 316L (special order) stainless steel, INOX CSSP is designed to provide reliable and corrosion-free service for extended periods.

CSSP provides a number of advantages when compared with ‘conventional’ pipes, as they are lightweight, flexible, require fewer connections and fittings and are less susceptible to extreme temperature and corrosive environments.

INOX CSSP conforms to SANS 1689 and has been tested rigorously to ensure an extended service life. INOX CSSP can maintain high operational pressures and a wide range of temperatures and is rated at 100 °C and 100 kPa. INOX CSSP is designed to work with brass compression fittings complying with SANS 1067-1.

To my mind, the most important attribute of INOX CSSP is that there are no joints in the piping runs: from the heat pump to faucet, for example – therefore, no leaks, and a definite specification for House Crawford.

Structural insulated panels (SIPs): SIPs are a high performance building system for residential and light commercial construction. The panels consist of an insulating foam core sandwiched between two structural facings, typically Chromadek (in South Africa). SIPs are manufactured under factory-controlled conditions and can be fabricated to fit nearly any building design. The result is a building system that is extremely strong, energy efficient and cost-effective.

SIPs share the same structural properties as an I-beam or I-column. The rigid insulation core of the SIP acts as a web, while the sheathing fulfils the function of the flanges. SIPs combine several components of conventional building, such as studs and joists, insulation, a vapour and air barrier. They can be used for many different applications, such as exterior walls, roofing, flooring and foundation systems.

The greatest advantage of SIPs is their ability to span considerable distances with no need for rafters or purlins – and, of course, their superior insulating capacity.

Cellulose insulation: Manufactured of pulverised paper and various forms of boric acid, the thermal performance of loose filled cellulose compares favourably to other types of insulation: about the same as or slightly better than fibreglass wool. But cellulose is very good at fitting around items in walls such as pipes and wiring, filling almost all of the air pockets, which significantly increases the overall insulation efficiency of a wall. Real world surveys have cellulose performing 20-30% better at reducing energy used for heating than fibreglass.

The simple fact of the matter is that cellulose will perform better and provide better protection in the event of a fire than any other commonly used type of insulation. "Paper burns, so why not cellulose insulation?" people ask, a comment easily countered. Place a small amount of cellulose insulation in your cupped hand. Place a coin on top and apply a blowtorch. The coin will glow without heat being transferred to your hand.
I've done it many times, so cellulose insulation is specified for House Crawford.

Other construction innovations to look out for include: translucent concrete, which is filled with optical fibres to up to 4.0 % of its mass; electrified wood, a sandwich of two electrical layers between layers of wood to allow, 'tapping off' of power virtually wherever you want it; Bendable concrete called Engineered Cementitious Composite (ECC), with a strain capacity in the range of 3.0 to 7.0%, compared to 0.01% for ordinary Portland cement (OPC); and transparent aluminium oxynitride, a replacement for window glass that is four times harder than fused silica glass.

Light steel frame (LSF) construction

One may ponder why LSF construction and the seemingly wonderful products associated with it such as cellulose insulation battle to gain market acceptance. For the latter, I know all too well, I was GM of the largest manufacturer of the product in the United States, HJH Chemicals, Phoenix, Arizona.

For LSF construction, I use the comments of Nardi van Zijl, an architectural designer whom we had the pleasure of meeting and 'co-opting' onto our House Crawford team. Here's his take on LSF:

“For many, the first exposure to LSF construction was via mass-market housing. This inevitably attaches a low-cost stigma to any product, regardless of the quality or any other benefits.

“In addition to the trade’s unwillingness to try a new system, architects, engineers and quantity surveyors are prone to sticking to what they know. This is largely because the importer, developer or distributor generally has very limited resources for training and educating the trades and professionals on all aspects – pros and cons – of their specific system. More often than not, the importer, developer or distributor will give up the market development of their specific system, which results in the trades and professionals labelling it 'fly by night' or a failure. Sometimes this is a well-earned tag, but in general, it is a thorn in the side of any remaining new systems.”

Thanks, Nardi. We hope the case study on House Crawford will provide a better understanding of LSF construction, through a step-by-step report on an actual build. SIPs, corrugated stainless steel pipe and cellulose insulation will be used, but not transparent aluminium.

Anyway, you wouldn't see it if it was there!

Click to download and read pdf.

BANNER 8

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