5.1 This test method determines the operational forces of sliding windows and doors by simulating force applied by hand directly to movable sash or panels. Breakaway and in-motion operating forces are measures of the ease of operation of fenestration products. Product specifications, building codes, and building specifications establish operating force limits as measures of product performance or limits for handicapped accessibility, or both.
5.2 Window and door performance standards for air infiltration and water penetration in some cases require operating force measurements to be made and reported as an indication of the operability of the test specimen.
5.3 Operating forces can vary significantly from unit to unit due to factors such as installation parameters, wearing of sliding or rolling parts, lubrication, stiffening or softening of weather-strip, and environmental factors (for example, humidity, temperature, accumulation of dirt, and so forth). Therefore, when applied to new product designs, this test method requires that units be tested in a laboratory under controlled conditions including accurate mounting (plumb, square, and level) following the manufacturer's instructions. Use of this test method in the field does not necessarily indicate the operating forces that are inherent in the particular window design, but rather, provides a measurement of the forces required for operation of the particular unit at the particular time. The user is cautioned that installation defects such as bowed jambs, racked frames, or inadequate anchoring can result in binding or sticking of movable components and increased operating forces.
5.4 This test method requires measurement of both breakaway and in-motion operating forces. Generally, breakaway force is higher than in-motion operating force due to the difference between static and dynamic friction coefficients or the presence of weather-stripping and sash pockets, or both. Traditional fenestration product standards have required determination of in-motion operating force in the opening direction only and referred to this simply as operating force.
5.5 This test method is intended to determine the forces required to operate a window or sliding door which is properly installed and which is operated by hand application of force to a handle, pull bar, or sash member. Application of force through jerking or impact motion is not measured or evaluated by this test method. Operating forces can be significantly different between the opening and closing directions of movement; therefore, this test method involves measurements in both directions of movement.
5.6 This test method provides for two procedures which include a dead weight test method (Test Method A) and a force gage test method (Test Method B) of applying and measuring forces required to operate a sliding window or sliding door. When properly applied, both test methods are deemed to produce equivalent results. The dead weight test method is considered to be less likely to be affected by the operator's skill in applying loads in a steady and properly timed manner. The force gage test method is considered simpler to apply and more applicable to field testing where the installation of pulleys and cabling is often impractical. Both test methods are subject to a similar uncertainty.