api 5000API Recommended Practice 500, 4th Edition. API has published API Recommended Practice (RP) 500, Classification of Locations for Electrical Installations at Petroleum Facilities• API 5000™ LCMSMS System • Turbo V™ source with ESI probe • Gas and source parameters: CUR: 20 psi, GS1: 40 psi, GS2: 40 psi, TEM: 350°C, CAD: 7, IonSpray voltage