|Standards Guidelines - Fibre or Micro Concrete Tiles (SKAT, 1992, 49 p.)|
What are FCR and MCR
FCR (Fibre Concrete Roofing) is a new roof covering technology. It consists of concrete tiles made of cement mortar mixed with a small amount of natural or synthetic fibre.
In the case of MCR (Micro Concrete Roofing) fine aggregate is used instead of fibre.
For further basic information please refer to The Basics of Concrete Roofing Elements.
The advantages of FCR and MCR
The technology provides an inexpensive and reliable roof cladding and suits especially the needs of developing countries. The main advantages are:
· The raw materials are available locally and thus foreign exchange is saved.
· The appropriate technology that is involved allows for decentralised and small scale production.
· The technology involves little investment.
· The production is labour intensive rather than capital-intensive, thus it creates jobs.
· During sun radiation, compared to metal sheeting, rooms covered with FCR/MCR remain cooler because of better thermal insulation and ventilation.
· During rain, compared to metal sheeting, FCR/MCR produces much less noise.
· The product is environmentally well adapted.
· The technology is easy to learn.
The drawbacks of FCR/MCR
The durability of FCR/MCR is basically as good as for ordinary concrete tiles, which have shown service lives exceeding 50 years. However, it may happen that the strength of tiles is lower in comparison with modern tiles and AC sheets. This mainly occurs when the production unit is too small and therefore unable to ensure a constant level of quality control or when standards for FCR/MCR tiles are not existing.
Why are National Standards important?
When a product is newly introduced in a country it must be reliable for the users. Also, potential users of the product should be convinced that a product is of good quality and this should be guaranteed.
In the case of FCR/MCR, the clear advantages of the technology will help the product to penetrate the market on a large scale. However, officially recognised quality standards are required to achieve this goal, because building control institutions usually depend on such standards to be in a position to certify the use of a product.
Quality standards will encourage decision makers, be it the house owners, the architects, contractors and engineers, or the project planners, to recommend and specify FCR/MCR as roofing material. They can guarantee for quality, safety and durability based on official recognition and legislation. This is specially important in governmental projects (schools, health centers, public housing schemes), where the respective institutions are obliged to respect building regulations.
The lack of standards is hence a potential inhibiting factor to the widespread adoption of this advantageous technology. Issuing National Standards for FCR/MCR would, therefore, contribute substantially to spreading its use.
Objectives of these Guidelines
The standardisation of FCR/MCR products constitutes the last step in the development of the technology. A standardisation of the product would cut out low quality producers or force them to improve their production.
Often the respective official bodies would be willing to issue such standards but are not in a position to do so because the required basic data are not available or not internationally and scientifically assured.
These guidelines aim at closing this information gap. They help official institutions, which issue quality standards for construction materials and building regulations on a national level, to design their own standards for FCR/MCR products which are valid for their specific country, taking into consideration the requirements and characteristics of the local context.
The guidelines also help architects, engineers, building control institutions and contractors to execute their own tests, in the event that national standards are not available or in case the quality of the product is questioned.
The methods described in these guidelines can also help to persuade customers and clients.
What you will find in these Guidelines:
Chapter 3 describes the main steps that are required when designing and implementing a National FCR/MCR Standard.
In chapter 4 the structure of such a standards document is proposed. It provides also sample text which helps to formulate a standards document. These texts are partly compiled from various existing standards and partly the content of the technical recommendations by RAS, and will have to be adapted, taking into consideration local conditions.
In the annex you find a description of the testing methods that are required to guarantee quality, safety and durability of the product, as well as information about common standards of dimensions and shape, fittings and fixing devices.
Basic data and limitation
These data are based on scientific laboratory research and long standing practical experiences over the last ten years by international technology specialists. However, the figures may vary from place to place depending on the raw material properties and other local factors. The experience in a particular country will provide the exact data that are to be applied.
What you will NOT find in these Guidelines:
The guidelines are not designed for newcomers who are interested in the technology in general. For basic information we suggest that the following booklet should be obtained: The Basics of Concrete Roofing Elements.
It is also not designed for producers who want to start or improve production and business. For them the various elements of the FCR/ MCR Toolkit are available, containing technical information on raw material specifications, description of production processes and equipment, as well as information on business questions such as marketing, financial and administration management.
Comments and feedback information are welcome and will help to further improve these guidelines and with it the technology. They may be sent to SKAT or ILO.