CNG certification exam — what's the pass score and how long should I study?
I'm planning to sit the CNG compressed natural gas certification exam next month and I can't find a clear answer on what the actual passing score is. Some sources say 70%, others imply it depends on the test form version. Anyone who's taken it recently know the definitive number?
My background is 4 years in fleet maintenance so I'm not coming in completely cold, but the fuel systems and pressure regulation content feels dense when I try to study it formally. I've been doing about an hour a day for the past 2 weeks and I'm probably at 65% on practice questions, which doesn't feel comfortable enough yet.
My test is in 28 days. Is that enough time if I push to 90 minutes daily? I'm most shaky on the cylinder inspection criteria and the station equipment section. The hands-on stuff I know from work but translating that into multiple-choice wording is a genuinely different skill.
28 days at 90 minutes daily is doable if you're disciplined about staying in your weak areas. Don't keep redoing questions you already know cold — force yourself into the cylinder and station equipment sections even when it's frustrating. That's where the exam hits hardest.
The pass mark is 70% last I checked, which was about 8 months ago. I scored 74% on my first attempt and it felt tight — the cylinder inspection questions are worded very precisely and one wrong word in the answer choices can trip you up. I'd budget 6 weeks if you have the option.
Fleet experience helps a lot for the practical scenario questions but the regulatory content is its own thing entirely. I spent 3 focused days just on NFPA 52 reference material and it probably saved me 5 percentage points on the actual exam. Worth the time even if it feels dry.