The method of testing for efflorescence given in These salts are sulphates of calcium, magnesium, AS/NZS 4456.6 classifies the unit as one of the aluminium, sodium, and potassium. categories in the table below. Table 4 Potential to efflorescence, categories and definitions in accordance with AS/NZS 4456.6. Category Definition Nil No observable efflorescence Slight No more than 10 percent of any surface of the specimen covered by a thin deposit of salt Moderate More than 10% of one surface but not more than 50% of the total specimen surface covered by a thin deposit of salt Heavy A deposit of salt covering more than 50 percent of the total brick surface Severe Any efflorescence that is accompanied by powdering and/or flaking of the surface of the specimen Figure 4 Brickwork effected by efflorescence Brick Properties Brick Technical Manual 11 1.7 Lime Pitting Lime pitting is an imperfection occurring in the surface of a brick due to the expansion of large lime particles just below the surface. The lime originates from the raw materials used in the manufacture of the bricks.

Special access floors 1.0 2.5 All other 1.0 1.25 Appendages and ornamentations 2.5 2.5 Signs and billboards 2.5 2.5 Other rigid components High deformability elements and attachments 1.0 3.5 Limited deformability elements and attachments 1.0 2.5 Low deformability materials and attachments 1.0 1.25 Other flexible components High deformability elements and attachments 2.5 3.5 Limited deformability elements and attachments 2.5 2.5 Low deformability materials and attachments 2.5 1.25 a Where justified by detailed analyses, a lower value for p is permitted, but shall not be less than 1. The reduced value of p shall be between 2.5, assigned to flexible or flexibly attached equipment, and 1, assigned to rigid or rigidly attached equipment. Many different scales and criteria are available which address the subjective evaluation of floor vibration. Factors included in these subjective evaluations include the natural frequency of the floor system, the maximum dynamic amplitude (acceleration, velocity, or displacement) due to certain excitations, and the amount of damping present in the floor system. At the present time, most of the design criteria utilize either a single impact function to assess vibrations, which are tran- TABLE 5.20 Mechanical and Electrical Components Coefficients Mechanical and electrical component or element p

Corner blocks are made of plastic or wood and use the tension of the string line stretched from end to end to keep them in position. They are easy to make from timber available on site. They make it quick and easy to adjust the string line up the wall for each course of brickwork to be laid. Look online at a building tool supplier website (start with Buck & Hickman.) Check out the types of corner blocks that they sell. Look at the corner blocks in Our House too, as an additional guide to how the blocks should appear. Corner block Having considered how we set out and build a straight wall, lets look at how we set out a wall that has corners specified for the design. In brickwork, a corner has an unusual name: a quoin. A corner or quoin, is usually set out as a right-angle; in other words it is set out at 90. (There are quoins set out to other angles that you will learn about as you progress to higher levels.) In Chapter 3 you will find more details about setting out squares and rectangles using a number of methods.