Fire and Materials: Volume 41, Issue 3 April 2017 Pages 275–288 doi.10.1002/fam.2386 July 2016 Flammability of Natural Plant and Animal Fibers: A Heat Release Survey Mary L. Galaska 1 , A. Richard Horrocks 2* , Alexander B. Morgan 1* 1 Center for Flame Retardant Material Science, University of Dayton Research Institute, 300 College Park, Dayton, OH 45469-0170 2 Institute for Materials Research and Innovation, The University of Bolton, Deane Road, Bolton, BL3 5AB, UK. Abstract: With increased interest in sustainable materials for use in building materials and clothing, there is a renewal in the use of natural fibers (plant or animal-based) vs. synthetic fibers in a variety of applications. However, there is not as much information available on the flammability of these natural fibers especially when they are used in products where purification techniques used in conventional textile processing are not required. The literature to date suggests that all of the fibers can be grouped into two categories: cellulosic and animal, with the assumption that regardless of original species, the flammability is similar for fibers within each category. In this report, we have conducted a survey via micro combustion calorimetry to determine if all cellulose-based and all protein based fibers are the same from a heat release perspective. Our findings show that this is not the case, and there are notable differences in fiber types within each genus. Further, how the natural fiber has been treated prior to use can have some dramatic effects on heat release caused by residual impurity content. The results in this paper suggest there is more to be learned about these natural fiber types in regards to their inherent flammability. Keywords: Micro combustion calorimetry, animal fibers, plant fibers, heat release Introduction: Use of naturally derived (plant and animal) materials for clothing, upholstery fabrics, building materials, or other household items has developed with human civilization over the past millennia, but more recently natural materials have become more in demand over the past decade or so due to an increase in sustainability initiatives. Sustainability initiatives such as Leadership in Energy & Environmental Design (LEED) 1 often request natural materials to be considered in building product design so that the products at end of life are easily bio-degradable and can be made from renewable natural sources with minimal environmental impact. Natural fibers derived from plants have long been used in buildings to reinforce adobe and mud bricks, and now are beginning to be used in modern composites as a replacement for synthetic reinforcing fibers made from glass or thermoplastic materials. One common example of such a composite would be wood-fiber board, which is often composed of cellulosic fibers with a synthetic polymer binder. With such an increase in natural plant fiber use in non-conventional textile areas, there have been some studies on how these fibers affect flammability in composites, 2,3,4,5,6,7,8, with the general conclusion that the cellulosic plant fibers assist with charring, but there has not been a systematic study of these fibers in how they may be different from one another in regards to flammability. While most plant fibers are predominantly cellulose based, where the fibers are located within the plant can result in a wide range of * Authors to whom questions should be addressed: alexander.morgan@udri.udayton.edu; a.r.horrocks@bolton.ac.uk