It is very important that door closers be installed precisely as recommended by the manufacturer. Experience has shown that a large percentage of troubles with closers results from disregard of mounting instructions. In response to various code requirements for room-to-corridor protection, closer manufacturers have produced products that provide automatic door closing but still allow flexibility. These units permit the door to be held open in many locations of hold-open and yet upon a signal from a smoke detector, the hold-open mechanism disengages and the closer causes the door to close. A similar type of unit incorporates a device allowing the door to swing free as though it were not equipped with a door closer. As with the multiple-point hold-open device just described, the swing-free model, upon a signal from a smoke detector, cancels the closer nullifying device and the closer causes the door to close. These units are suitable in a variety of occupancies, particularly institutional. Barrier-free provisions for disabled people dictate certain minimum opening resistance of doors. Depending upon the jurisdiction and location of doors, these forces range from a 5-lb force maximum to a 15-lb force maximum. There will be instances, because of the door size or air-pressure conditions, when the necessary closing force exerted by the closer to overcome these conditions will create opening resistance in excess of what is permitted. Power-operated doors or doors with a power assist specially made to solve this problem are recommended as a practical

If the decision is to cut the bricks to establish proper bonding, then we need to use the methods and tools already discussed in the previous section. Since it is important to maintain accuracy in building our wall, we need to ensure that the first course that we lay is level and Stretcher bond When deciding which method to use in order to establish correct bond, discuss it with your supervisor or an experienced fellow worker. Its always good to check. accurately aligned, as required by the working drawing. The next section will discuss in detail the methods and sequence we use to achieve this. Whilst Stretcher bond can be termed half-bond, there are other bonds which can be termed Quarter bond. The most common of these are Flemish bond and English bond. These are used where a thicker wall is needed for greater strength. Using these bonds results in a wall that has a width equal to the length of the stretcher face of a brick (215mm) and are therefore referred to as one-brick walling.

Paint selection and surface preparation are a matter of economics. For example, while blast-cleaned surfaces are concealed to be the best paint foundation for lasting results, the high cost is not always justified. Nevertheless, the Council specifies a minimum surface preparation by a blast cleaning process for such paints as alkyd, phenolic, vinyl, coal tar, epoxy, and zinc-rich. As an aid for defining and evaluating the various surface preparations, taking into account the initial condition of the surface, an international visual standard is available and may be used. A booklet of realistic color photographs for this purpose can be obtained from the Council or ASTM. The applicable standard and acceptance criteria are given in Quality Criteria and Inspection Standards, American Institute of Steel Construction. The Council stresses the relationship between the prime coat (shop paint) and the finish coats. A primer that is proper for a particular type of field paint could be an unsatisfactory base for another type of field paint. Since there are numerous paint formulations, refer to Council publications when faced with a painting condition more demanding than ordinary. In the absence of specific contract requirements for painting, the practice described in the AISC Specification for Structural Steel for Buildings may be followed. This method may be considered nominal. The steel is brushed, by hand or power, to remove loose mill scale, loose rust, weld slag, flux deposit, dirt, and foreign matter. Oil and grease spots are solvent cleaned. The shop coat is a commercial- quality paint applied by brushing, dipping, roller coating, flow coating, or spraying to a 2-mil thickness. It affords only short-time protection. Therefore, finished steel that may be in ground storage for long periods or otherwise exposed to excessively corrosive conditions may exhibit some paint failure by the time it is erected, a condition beyond the control of the fabricator. Where such conditions can be anticipated, as for example, an overseas shipment, the engineer should select the most effective paint system. There is some question as to justification for protecting steelwork embedded in masonry or in contact with exterior masonry walls built according to good workmanship standards but not impervious to moisture. For example, in many instances, the masonry backing for a 4-in brick wall is omitted to make way for column flanges. Very definitely, a 4-in wall will not prevent penetration of water. In many cases, also, though a gap is provided between a wall and steelwork, mortar drip- pings fall into the space and form bridges over which water may pass, to attack the steel. The net effect is premature failure of both wall and steel. Walls have been shatteredsheared through the brickby the powerful expansion of rust formations. The preventatives are: (1) coating the steel with suitable paint and (2) good