Ozone Friendly products




Q) Is it safe?

A) TASS is essentially a concrete coffer slab system, designed on the same principles.

The polystyrene TASS blocks act as the void formers only, playing no structural role and stay in place to thermally insulate the building.

The method of pouring concrete between the TASS blocks to create the beams and slab, fully encapsulates the rebar creating a monolithic structure of reinforced beams and concrete topping.

During construction, after propping the TASS deck, it can be worked on and concrete poured with complete safety. The TASS deck which is made from 350MPa cold rolled steel ‘ribs’ and high density moulded polystyrene blocks safely carries workers installing rebar, mesh and controlling the concrete pour. Unlike concrete rib and block systems the TASS blocks do not crack or break leading to possible worker injury.

TASS has been installed since the beginning of 2005 without any cases of structural failure or injury during construction.

Q) Am I taking a risk using TASS?

A) TASS has had over 3 years of successful use in South Africa in wide ranging projects from residential to apartment blocks and high rise commercial buildings.

The design and installation of TASS is always controlled by appointed structural engineers.

The design of the system complies fully with the relevant structural design codes for concrete suspended floor slabs.

Q) Where can I get a TASS slab?

A) TASS is supplied only through appointed TASS licensees who are either structural engineers or builders aligned with structural engineers.

Licensees are fully trained in the system and take responsibility for the design and installation of TASS.

Details of TASS licensees can be obtained from the ABP website or by contacting ABP directly.

Q) Can any builder install TASS?

A) Yes. The advantages for the builder are many.

- The components are all lightweight and therefore no heavy lifting equipment is needed.

- As the system components are made to tight tolerances it fits easily and neatly together.

- Installation crews of half the size used to install concrete rib and block systems can place TASS decks significantly faster.

- Movement of TASS components around site is easy.

- Service ducts and electrical and plumbing services can be cut into the TASS blocks with a hand saw as can the blocks to fit into the wall constraints.

- The installation process is a similar but simplified, easier and safer method to laying a concrete rib and block deck.

- Compared to installing in situ and coffer slabs TASS requires much less installation equipment – no decking, scaffolding and separate edge forming only support propping.

- If required ABP can supply on site installation training

Q) Can a TASS slab support heavy loads?

A) TASS can support heavy loads associated with carrying machinery and equipment, multi storey building and people typical of all industrial, commercial and residential buildings. The load supporting capability is designed into the system using the variables of; support beams and columns, slab beam depth, reinforcement configuration and concrete strength.

Q) How do I finish the ceiling under a TASS slab?

A) There are 3 options;

1) Apply the EPS plaster system Polyplast. The bottom of the TASS blocks have a 5mm dovetail groove to help hold the plaster when plastering. Polyplast is applied in a two stage process with a scratch coat applied on day 1 and the finish coat on day 2. Polyplast has excellent adhesion to both the steel rib and the polystyrene TASS blocks, can be smooth finished and does not crack over time.

2) Fit a suspended ceiling. The droppers are fixed to the underside of the steel channel which run at 600mm centres.

3) Paint the ceiling. For parkades and basements which do not need a high aesthetic finish the under side of the TASS slab can be painted with any high quality, acrylic, water based paint. The advantage of TASS is that as the components fit closely together and the underside is therefore flat, a painted finish is perfectly acceptable.

Q) What happens if there is a fire?

A) The structure of a TASS slab is the same as a concrete coffer slab with the polystyrene playing no structural role.

The polystyrene used to manufacture the TASS blocks is a fire retardant grade of material and will self extinguish if the source of flame is removed. In a fire the polystyrene will melt leaving the concrete coffer slab structure in place. The fumes given off from the melting polystyrene are no more harmful than that from other organic materials used in buildings.

For behaviour of EPS in fire visit the Expanded Polystyrene Association website: www.epsasa.co.za.

Q) Is a TASS slab cheaper?

A) When evaluating cost you need to look at 4 things: material cost, design complexity, installation cost and life cycle cost.

Material cost – in general terms expanded polystyrene (EPS) is about half the cost of concrete so where EPS replaces concrete it will be cheaper. EPS replaces the concrete blocks in rib and block systems and concrete in in situ slabs.

With the combination of 350MPa cold rolled pregalvanised rib and the EPS block, TASS is price comparative with concrete systems of prestressed concrete ribs and cement blocks. From a material cost standpoint TASS is less expensive than concrete in situ slabs.

Design complexity – where complex designs are required incorporation angles, split levels and curves TASS offers increased versatility as the blocks and channels and easily be cut to size/shape and in the same support design different height TAS blocks can be used to cope with different levels.

Installation cost – this is the area where the TASS system offers significant cots advantage over competitive systems.

vs Concrete rib and block

The TASS system components are lightweight and can be installed without heavy lifting equipment or large labour crews, quickly.

TASS decks can be placed with 2 operators positioning the channels and spacing them correctly with TASS blocks at the wall ends and then sliding the blocks into position and cutting them to fit at wall ends. Similarly small crews can move the TASS blocks and channels around site and up into multi storey buildings.

Typically installation crews of half the size of concrete rib and block crews can install TASS at a faster rate.

The propping spacing can be extended as the dead load of a TASS slab is 150kg/m² less than an equivalent concrete rib and block slab. Typically from 1,2m centres to 1,6 m centres along the ribs.

Electrical and plumbing services can easily be cut into the TASS blocks using a hand saw

vs Concrete in situ slabs.

TASS does not require the extensive decking of in situ systems and the time it takes to place this. TASS edge forming can be easily done with tack welding channels to the edges of the ribs removing the need for extensive timber edge shuttering and support systems.

Overall the installation of a TASS deck is substantially faster then in situ formwork saving time, materials and money.

vs Coffer slab systems

Once again coffer slabs require extensive decking to position and hold the coffers in place.

As stated TASS is in essence a coffer slab system where the void formers remain in place.

Conventional coffer void formers have to be removed and transported away from site whereas TASS remains in place removing this second operation saving time and money.

Life cycle cost – the key benefit of TASS over concrete systems is the thermal insulation the system provides. This will reduce significantly the energy costs associated with heating and cooling over the life cycle of the building. In commercial buildings and shopping centres the size and capital costs of air conditioning units can be reduced taking into account this insulation effect.

Q) What is the spanning capability of a TASS slab?

A) The TASS system has 4 different block heights with the largest being the 365mm TASS block, which gives a final slab thickness of 425mm. This slab can free span (i.e. unsupported except for the slab perimeter) up to 11metres.

Q) How much concrete do I need for a TASS slab?

A) This varies according to the height of the TASS blocks with the deeper blocks requiring more concrete basically as the concrete beams between the TASS blocks are deeper. The concrete requirement per m² of TASS slab for each different block size detailed on the TASS data sheet and ranges from 0,11 to 0,17m³ of concrete per m² of slab.

As can be seen the amount of concrete used in a TASS slab does not vary greatly from thinnest to deepest TASS slab. This is what makes TASS slabs cost competitive against concrete slabs particularly in situ slabs.

Q) How quickly can you deliver the TASS components?

A) The TASS expanded polystyrene blocks are supplied ex stock and the support channels are also ex stock items. The only delay on the channel supply is that the channels have to be cut to length to match the dimensions of the measured building plan.

This is opposed to concrete components which have to be moulded (normally one product per mould per day) and then cured to gain strength before they can be used.

Q) Can I use TASS in a multi storey building?

A) Yes, TASS structurally is a concrete coffer slab system. The advantages of TASS in multi storey buildings are: 1) the components are lightweight so can be moved up and into the building easily with limited labour and no heavy lifting equipment 2) the dead load of a TASS slab is 150 and 320 kg/m² less than a concrete rib and block and in situ slab respectively. This has beneficial implications for the overall structural design of the building.

Q) How much does a TASS slab cost?

A) Cost depends on a number of factors: 1) Size of slab, 2) Span, 3) Location of project 4) Complexity of design. In order to get a TASS quotation building plans must be sent to a TASS licensee (available on the website: www.ABPbuildingproducts.co.za).

The full cost of a TASS slab will include the TASS design and supply, installation cost plus cost of the concrete topping.

Q) Do I have to prop a TASS slab?

A) Yes, to support the weight of the concrete until the concrete has cured a TASS deck has to be propped. The routine is to place the support channels and TASS blocks and then prop. Propping is typically at 1,6 metre centres. Half the props can be removed after 7 days and the balance after 14 days. Propping and de propping should always be done in consultation with you TASS licensee.

Q) Where can I see a TASS slab?

A) Once a TASS slab is fully installed it looks like any traditional slab. If you contact a TASS licensee or ABP Building Products representative you can be guided to a TASS project in progress in your area.

January 2008




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