JI SHIELD System 1 is a complete steel roofing system which features a 0.7mm outer and 0.4mm liner offering Class C non-fragility, which means that safety netting should remain in place until the top sheet (outer profile) is fully installed. This assembly provides a highly cost-effective roof system that is ideal for all types of commercial roof construction. Please contact us for more information. Information below must be used in conjunction with the appropriate NBS Specification document.