Book 19 defines interface specifications, including the keep-out volumes, for LED modules and lens plates enabling IP protection. It thereby enables an ecosystem of LED modules and lens plates delivered by multiple vendors. For the luminaire manufacturer, this guarantees a stable luminaire design platform wherein different LED modules and lens plates from different vendors can be designed-in.

Book 19 allows for slim luminaire design and higher optical efficiency since no protective cover is needed to make the luminaire IP protected. The ecosystem of LED modules and Lens plates available in the market make it possible to refurbish luminaires during their lifetime with new module-lens plate combinations thus fostering circular economy.

The modules require a separate LED driver (electronic control gear), and usually will be mounted on a heat sink. The maximum outline of the LED module is W 45 mm x L 146.6 mm. The IP protection can be obtained by applying a gasket on the heatsink around the LED module. This gasket is pressed by the lens plate to the heatsink. The modules with lenses are typically used for outdoor lighting applications, including roadway, pathway and outdoor-area lighting.

The specification defines several mechanical attributes of the LED modules, to enable accurate alignment with the lenses and fitting the modules in the luminaire. Performance characteristics of the LED module and lens plates are intentionally outside the scope of this specification to enable differentiation and innovation.