From retardant + -cy.
retardancy (plural retardancies)
- The degree of being retardant
1982, United States-Japan Cooperative Program in Natural Resources. Panel on Fire Research and Safety, Fire Research and Safety[1], page 2:The methods for evaluating flame and fire retardancy of these materials have been already established.
2009, T. Richard Hull, Fire Retardancy of Polymers: New Strategies and Mechanisms[2], →ISBN:
2014, Polymer Green Flame Retardants: A comprehensive Guide to ...[3], →ISBN:Fire safety legislation dictates, in particular, designing products of high-flame retardancy along with minimal environmental impact.