1. A Selection of SI Units and their Decimal Multiples

2. Properties of Engineering Materials

* Compressive values

Note: All properties in this table are indicative of the probable range of values for each class of material. The mechanical properties (strengths and E values) given are for short term loading conditions. The properties of specific materials will be dependent on their composition, that is on the properties and proportions of their constituent materials, including moisture content. Their mechanical properties may additionally be dependent on their temperature and age and the rate of loading.

3. Coefficients of Linear Thermal Expansion of Engineering Materials

4. Calculation of Dew-Points for Application of Coatings

Table of determination of dew-point

^(*) Example

With an air temperature of +10ºC (+50ºF) and 80% relative humidity, dewing starts when the structure/ substrate temperature is as low as +6.7ºC (+44ºF). If the contact thermometer shows a value only slightly above the dew-point temperature or below it, application of coatings should not be carried out.

The following procedure is to be adopted for dew-point control:

1. Attach contact thermometer to the structure (wait 15 minutes before reading the temperature so that thermometer can settle down to final temperature).
2. Read air temperature.
3. Read relative humidity of the air.
4. Look up dew-point temperature in chart (at point of intersection between air temperature and relative humidity).
5. Read object temperature on contact thermometer. If this is approximately 3ºC (5 - 6ºF) above the dew-point in the chart, then there is no objection to going ahead with the coating application. However, if the temperature of the structure is close to the dew-point or even below it, then work should be halted or not start due to the risk of condensation.

5. Curing of Cementitious Products

As with all cementitious materials, the correct curing is very important with repair mortars, renders and screeds. For products with a low w/c ratio it is necessary to ensure that sufficient water is retained for full cement hydration, and to minimize cracking.

Example: The table shows the quantity of water which evaporates at the surface if no curing takes place. With the following example we have a loss of approximately 0.6 litres per square meter per hour (l/m²h). This example is calculated with a 23ºC air temperature, a 50% relative air humidity, a 20ºC mortar temperature, and a 20 km/hr wind speed.

Curing methods should be adopted to maintain an evaporated quantity of water below 1.0kg/m²h.

6. PU flex Joint Sealant Design Considerations

Width to Depth Ratio

Facade joint widths are normally in the range 15 to 30mm and the optimum width to depth ratio for facade sealing is 2:1.

For joint widths up to 12mm

Minimum depth = 6mm

For joint widths 12mm - 40mm width 1

The base of the joint must not restrict the deformation of the sealant since this could result in failure during joint opening. The depth of the joint should be adjusted by inserting Joint Backing Rod. If applying over a filler board or similar a Bond Breaker Tape must be applied.

In corner joints the insertion of a strip of Backing Rod is required, otherwise the sealant will fail during movement of the joint.

There is an absolute limit to depth of 6mm the minimum to ensure adequate bond area for long term durability. Deep sections may be used in certain circumstances eg. where the seal is subject to traffic or pressure.

7. Namikaran Product Consumption Guide

(i) PU flex Sealants

Consumption Guide (for rectangular joints)

(ii) Namikaran Solvent-free Resin and Mortar Systems

Kg/m²/mm thickness = Applied thickness (mm) x Specific Gravity

(iii) Namikaran Solvent and Water Based Coatings

Note: The above is a theoretical guide only. Allowances must be made for surface profile, wastage etc.