Type Designation DS : A diesel-powered unit that, in addition to meeting all the requirements for Type D units, is provided with additional safeguards to the exhaust, fuel, and electric systems
NFPA 505 Fire Safety Standard for Powered Industrial Trucks Including Type Designations, Areas of Use, Conversions, Maintenance, and Operations, 2002 ed. (Std: Fr Sfty for Powered Ind Trucks Incl Type Designations, Areas of Use, Covr, Maint and Opr - Amer) {328 NFC}