Guaranteeing Equipment Safety for Firefighters Act of 2020 This bill requires the National Institute of Standards and Technology (NIST) to study and report on the contents and composition of certain firefighting equipment. Such study shall examine perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as PFAS, in new and unused personal protective equipment (PPE) worn by firefighters. PFAS are man-made substances that may have adverse human health effects, and which are contained in a variety of PPE. Specifically NIST must study (1) the identity, prevalence, and concentration of PFAS in such PPE; (2) the conditions and extent to which PFAS are released into the environment from the degradation of such PPE from normal use by firefighters; and (3) the relative risk of exposure to PFAS faced by firefighters. NIST shall issue a solicitation for research proposals to carry out recommendations from its report and award grants to applicants that submit proposals to develop safe alternatives to PFAS in firefighters' PPE.