The NFPA 855 standard, developed by the National Fire Protection Association, provides detailed guidelines for the installation of stationary energy storage systems to mitigate the associated hazards.
[pdf] If you wish to avoid the need for planning permission, the panels must:Not be installed above the highest point of the property (not including chimneys)Be fitted in a way that least affects the external appearance of the property and the surrounding areaNot protrude more than 200mm from the surface of your roof
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