Exin CDCS Exam - Topic 2 Question 24 Discussion

Actual exam question for Exin's CDCS exam

Question #: 24
Topic #: 2

FM-200 is phasing out as a halocarbon gas and management has decided to replace this with the more environmentally friendly Novec-1230 gas. Should you use exactly the same formula and parameters to calculate the gas content for the Novec-1230 gas?

AYes, as long as the temperature in the computer room has not changed

BYes, if you take the difference between the net and gross volume into account

CYes, as long as you use the same units of measure (kg/m or lbs/ft)

DYes, if you change the S-factor of the formula to reflect the gas type used

Show Suggested Answer

Suggested Answer: D

Halocarbon agents such as FM-200 (HFC-227ea) and Novec-1230 (FK-5-1-12) are both defined under NFPA 2001 and ISO 14520 as clean agents, but their required design concentrations and physical properties differ. When calculating agent quantity, the minimum extinguishing concentration (MEC) and safety factor (S) must be taken into account. The S-factor is specific to each agent and reflects differences in molecular weight, density, and flame suppression chemistry.

For Novec-1230, the required design concentration is generally lower than for FM-200 (around 4.5--6% vs. 7--9%), but the calculation formula is the same except for substituting the correct S-factor. Therefore, you cannot reuse the exact formula parameters from FM-200; you must change the S-factor and apply Novec-1230's physical constants.

This ensures compliance with NFPA 2001 Annex C, which provides correction formulas for room volume, temperature, and specific agent type. Using the wrong S-factor could result in underfilling or overfilling, compromising fire safety or increasing cost unnecessarily.

by Louvenia at Jan 05, 2026, 05:16 AM

Limited Time Offer

25%

Off

Get Premium CDCS Questions as Interactive Web-Based Practice Test or PDF

Contribute your Thoughts:

Submit Cancel

Domitila

3 days ago

Same units are a must, but the gas type matters too!

upvoted 0 times

...

Annabelle

8 days ago

Wait, are we really just swapping gases without recalculating? Seems risky.

upvoted 0 times

...

Arthur

13 days ago

Totally agree, the S-factor is key here!

upvoted 0 times

...

Jess

18 days ago

I think you need to adjust for the different properties of Novec-1230.

upvoted 0 times

...

Christiane

24 days ago

Wait, we're supposed to do math for this? I thought this was a certification exam, not a math test!

upvoted 0 times

...

Shawna

29 days ago

Novec-1230? More like Novec-1337, am I right? *wink wink*

upvoted 0 times

...

Vincenza

1 month ago

C) Yes, as long as you use the same units of measure (kg/m or lbs/ft). Units are everything in these calculations!

upvoted 0 times

...

Annamae

2 months ago

A) Yes, as long as the temperature in the computer room has not changed. Temperature is the key factor here, right?

upvoted 0 times

...

Alison

2 months ago

B) Yes, if you take the difference between the net and gross volume into account. Gotta factor in that extra space, you know?

upvoted 0 times

...

Gabriele

2 months ago

D) Yes, if you change the S-factor of the formula to reflect the gas type used. That's the only way to ensure the calculation is accurate for the new gas.

upvoted 0 times

...

Adolph

2 months ago

I recall that we should consider the specific characteristics of each gas, so I’m leaning towards needing to change something in the formula for Novec-1230.

upvoted 0 times

...

Hoa

3 months ago

I feel like we discussed how temperature can affect gas calculations, but I’m uncertain if that’s enough to justify using the same formula.

upvoted 0 times

...

Rodney

3 months ago

I think we practiced a question where we had to adjust the S-factor for different gases, so maybe option D is the right choice here?

upvoted 0 times

...

Timmy

3 months ago

I remember studying that different gases can have different properties, so I’m not sure if the same formula applies directly to Novec-1230.

upvoted 0 times

...

Alease

3 months ago

Wait, I'm a little confused. Doesn't the fact that they're switching gas types mean we need to recalculate everything? I'm not sure we can just plug in the new gas and expect the formula to work. I'll need to review the underlying principles to make sure I'm approaching this correctly.

upvoted 0 times

...

Carin

3 months ago

I feel pretty confident about this one. As long as the temperature and units are the same, I think we can use the same formula. The only thing that might need to change is the S-factor to account for the new gas type. I'll double-check that, but otherwise it should be straightforward.

upvoted 0 times

...

Darnell

3 months ago

Okay, I've got a strategy for this. I'll start by reviewing the formula we used for FM-200 and identifying the variables. Then I'll research Novec-1230 and see which of those variables might need to be updated. Shouldn't be too tricky.

upvoted 0 times

...

Demetra

4 months ago

Hmm, I think the key is in the differences between the two gas types. We'll need to look at the properties of Novec-1230 and see how they compare to FM-200. The S-factor might need to be adjusted.

upvoted 0 times

...

Walton

4 months ago

I'm not sure about this one. The question seems to be asking if we can use the same formula, but the gas type is changing. I'll need to think carefully about the factors that might change.

upvoted 0 times

...