ICC CN Exam Day: Bring a Calculator and Know What It May Be

Most ICC fire exams are lookup exams. CN is partly a maths exam, and that changes what you carry and how you pace.

ICC publishes Calculations as its own domain worth 20% — twelve of sixty questions of secondary-power battery sizing, voltage drop and conduit fill. You will be running those calculations, not just reading someone else's.

The format

Questions	60
Time	2 hours
Per question	2 minutes
Book policy	Open — you bring your own references
Pass mark	75%
Delivery	ICC PRONTO remote proctoring, or a Pearson VUE test centre

Two minutes a question is workable for lookup. It is tight for a battery calculation you have not practised. Twelve arithmetic questions at three minutes each consumes 36 of your 120 minutes, which leaves well under two minutes for everything else.

That arithmetic is the pacing problem on this exam. Practise the calculations until they take ninety seconds, or they will eat the paper.

The calculator question

Check the calculator policy for CN on its page in the ICC Exam Catalog, and check it again close to your exam date. Testing policies on permitted devices are set per exam and per delivery method, and a programmable calculator that is fine in one context is confiscated in another.

The safe default is a simple, non-programmable, non-communicating calculator with no stored formulas. If you are testing via PRONTO, confirm what the proctor will accept on camera before exam day rather than discovering it during the room scan.

Never plan on your phone. It will not be permitted under any delivery method.

What you may carry in

• References must be bound — original bound book, three-ring binder, or stapled.
• No photocopies of copyrighted material.
• Permanently attached tabs are allowed — ones that cannot be removed without damaging the page.
• Pre-existing highlighting and ink notes are fine.
• You may not write in your references during the exam. Scratch paper or an on-screen notepad is provided.

That last pair catches people: a book you annotated last year is welcome; annotating during the exam is not.

Tab for a documentation-heavy paper

CN's weighting is more concentrated than CA's, and it points somewhere different:

Domain	Weight	Tab priority
Documentation / Plan Reading	34%	Heaviest — NFPA 72 Ch. 7
Control Panel, Wiring and Equipment	25%	Ch. 10 and 12, NEC
Calculations	20%	NFPA 72 10.6, NEC Art. 760 tables
Notification Appliances	6%	Ch. 18
Initiating Devices	5%	Ch. 17
Functional Control Interfaces	5%	Ch. 21
General Administration	5%	IFC, IBC

Documentation, control equipment and calculations are 79% of the paper. Notification and detection — the material most fire alarm people know best — are 11% between them. If your preparation is weighted toward devices, it is weighted toward a ninth of the exam.

Tab Chapter 7 first. It is the largest domain and the one experienced installers under-prepare, because record-of-completion content is not what you learn on a job site.

The three calculations to have cold

1. Secondary power (battery) sizing — 24-hour standby plus alarm load, derating, and the safety factor. NFPA 72 10.6.
2. Voltage drop — end-of-line voltage at the furthest appliance on a notification circuit.
3. Conduit fill — NEC Chapter 9 tables, and Article 760's power-limited rules.

These recur. A plans examiner re-performs the submitted calculation and checks it, and the exam tests that directly.

PRONTO or a test centre

PRONTO means your own desk, your own books, your own calculator — subject to the proctor accepting it on camera. Pearson VUE removes technology risk. Either way, confirm the calculator policy first: it matters more on CN than on any other exam in this family.

If you do not pass

Six attempts within a six-month period, fee payable each time. Exhaust all six and you wait six months from your first attempt.

Before you go

Read the full domain breakdown and check your prep against the weighting. Our free 10-question practice test draws from the same weighted pool.