A: 06 m (2) or 7.6 m (26 ft) maximum spacing B: Air terminals are located within 0.6m (21) of ends of ridges FIGURE 4.8.2 Air Terminals on Pitched Roof. 4.8.2.1 Strike termination devices shall be placed on ridges of pitched roofs and around the perimeter of flat or gently sloping roofs at intervals not exceeding 6 m (20 fi. 4.8.2.2. Strike termination devices 600 mm (24 in.) or more above the object or area to be protected shall be permitted to be placed at intervals not exceeding 7.6 m (25 fi) 4.8.2.3 Pitched Roof Area. (A) A pitched roof with eave heights of 15 m (50 ft) or less above grade shall require protection for the ridge only where there is no horizontal portion of the building that extends beyond the eaves, other than a gutter. (B) Pitched roofs with eave heights more than 15 m (50 ff) shall have strike termination devices located according to the 46 m (150 ft) geometric model. [See Figure 4.7.3.1(B) and Figure 4.7.3.3.) 4.8.2.4 Flat or Gently Sloping Roof Area. Flat or gently sloping roofs that exceed 15 m (50 #) in width or length shall have additional strike termination devices located at intervals not to exceed 15 m (50 ft) on the flat or gently sloping areas, as shown in Figure 4.8.2.4(a) and Figure 4.8.2.4(b), or such area can also be protected using taller air terminals that create |zones of protection using the rolling sphere model so the sphere does not contact the flat roof area. Copyright NFPAA: 15 m {80 ft) maximum spacing between air terminals B: 45 m (150 ft) maximum length of cross run conductor permitted without a connection from the eross run conductor to the main perimeter or down conductor ©: 8 m (20 tt) oF 7.6 m (25 ft) maximum spacings botwoon air terminals along edge FIGURE 4.8.2.4(a) Air Terminals on Flat Roof. As 15 m (59 ft) maximurn spacing 8: 6m (20 ft) oF 7.6 m (25-11) maximum spacing Copyright NFPAFIGURE 4.8.2.4(b) Air Terminals on Gently Sloping Roof. 4.8.3* Dormers. 4.8.3.1 Dormers as high or higher than the main roof shall be protected with strike termination devices, conductors, and grounds, where required. 4.8.3.2. Dormers and projections below the main ridge shall require protection only on those areas extending outside a zone of protection, 4.8.4 Roofs with Intermediate Ridges. Strike termination devices shall be located along the outermost ridges of buildings that have a series of intermediate ridges at the same intervals as required by 4.8.2. 4.8.4.1. Strike termination devices shall be located on the intermediate ridges in accordance with the requirements for the spacing of strike termination devices on flat or gently sloping roofs. 4.8.4.2 If any intermediate ridge is higher than the outermost ridges, it shall be treated as @ ‘main ridge and protected according to 4.8.2. 4.8.5 Flat or Gently Sloping Roofs with Irregular Perimeters. Structures that have exterior wall designs that result in irregular roof perimeters shall be treated on an individual bi 4.8.5.1. The outermost projections form an imaginary roof edge that shall be used to locate the strike termination devices in accordance with 4.8.2. 4.8.5.2 Inall cases, however, strike termination devices shall be located in accordance with Section 4.8, as shown in Figure 4.8.5.2. Copyright NFPAA: Aie terminals within 0.6 m (2 tt) of ee) Outemost projection of roof edge FIGURE 48.5.2 Flat or Gently Sloping Roof with Irregular Perimeter. 4.8.5.3 Strike termination devices installed on vertical roof members shall be permitted to use a single main-size cable to connect to a main roof conductor. 4.8.5.4 The main roof conductor shall be run adjacent to the vertical roof members so that the single cable from the strike termination device is as short as possible and in no case longer than 4.9 m (16 ft) 4.8.5.5 The connection of the single cable to the down conductor shall be made with a tee splice, as shown in Figure 4.8.5.5 Copyright NFPA