Civil Engineering Reference
In-Depth Information
however, laboratory procedures, i.e. they would not be appropriate for QA
purposes on site. BS EN1504-10 (BSI, 2003) covers Quality Control of the
works and includes testing that can be carried out on site.
Whilst manufacturers usually take responsibility for many of these
Standard tests, there are a number of requirements that must be noted by
specifiers, exemplified as follows.
• For hydrophobic impregnations, there are two classes that relate to the
depth to which the material penetrates the concrete on standard test
blocks: Class I is < 10 mm, and Class II is > 10 mm. Similarly, there
are two classes for drying rate coefficients. There is also a performance
characteristic for resistance to diffusion of chloride ions.
• For pore-blocking impregnations, there are three classes of permeability
to water vapour (Class I, permeable; Class II, medium permeability and
Class III, dense against water vapour). Similarly, for impact loading there
are three classes: Class I is the lowest, Class III is the highest impact
resistance. Also, there are three classes for slip and skid resistance,
dependent on the exposure (inside wet surfaces, inside dry and outside),
although these classes may be modified to meet national regulations.
• For coatings, there are two classes for withstanding abrasion by
traffic. Three classes for water vapour are also present, similar to
impregnations. Thermal compatibility is divided into trafficked or
untrafficked conditions for adhesion after various exposure cycles,
with further subdivision into flexible, crack-bridging or rigid systems.
For crack-bridging systems, the required crack accommodation should
be selected by the designer with respect to local conditions, with
no
failures allowed. The impact resistance is again split into three
categories, and there are two classes for antistatic coatings dependent
on environment.
The final sections of BS EN 1504-2 consist of informative annexes:
•
Annex A gives an example of the minimum frequencies of manufacturer's
testing.
•
Annex B gives useful examples of what designers need to specify for
three separate cases.
•
Annex C relates to the release of dangerous substances.
•
Annex Z, which is over 30% of the document, relates to the Construction
Products Directive and certification of conformity.
As with other parts of BS EN 1504, conformance to this part of the
Standard does not guarantee that applying a surface protection system will
provide the required level of performance. Even if the chosen system is the
correct type, it does not guarantee that the material has been properly applied
on site (appropriate and very useful site-tests are given in BS EN 1504-10).
