CIH Exam Prep, Documented as It Happens
SPEP built its CRSP and CRST question banks after passing both exams — mapping exactly what gets tested. CIH is being built the opposite way: the founder is studying and sitting the exam himself, sharing every reference guide and tool along the way. No finished question bank yet — but a real study journal, a growing set of reference guides, and a working Equation Master you can use today.
Everything Written So Far
Free reference guides pulled directly out of real CIH study notes — no sign-up required for any of them.
What Is CIH? The Certified Industrial Hygienist Credential
What CIH actually certifies, the 16 knowledge domains it covers, who administers it, and how it compares to CRSP and CRST.
Learn the basics → STUDY JOURNAL
My CIH Exam Journey: Study Journal & Scouting Strategy
A live study journal documenting the CIH exam prep process — knowledge unit tracking, question type patterns, and a phase-by-phase scouting strategy for ABIH candidates.
Follow along → REFERENCE
CIH Exam Eligibility: Complete BGC Requirements Checklist
Every CIH eligibility requirement explained — STEM credits, IH coursework, the Big Four pillars, ethics hours, professional experience, and reference options — sourced from BGC's official checklist.
Check eligibility → REFERENCE
CIH Calculator & Math Basics
The math skills behind every CIH equation — logs, exponents, roots, ratios — explained plainly with worked examples, exact calculator keystrokes, and a free practice calculator.
Refresh your math → REFERENCE
CIH Exam Equations: Complete Formula Reference
Every equation on the CIH exam — ventilation, noise, statistics, heat stress, and radiation — rendered with a plain-language variable key for each formula.
View equations → REFERENCE
CIH Radiation Units: Imperial vs. SI Conversion Guide
Curie, Roentgen, rad, rem and their SI equivalents, explained as a chain from source activity to biological dose — with a full conversion table.
View units guide → REFERENCE
HVAC Air Cycle: Complete Airflow Reference
Outdoor air, mixed air, supply air, return air, exhaust, make-up air — the full HVAC cycle explained stage by stage, with the complete OA/RA/MA/SA/EA/MUA terminology table.
View airflow guide → REFERENCE
Industrial Toxicology Reference
69 substances across 8 chemical families — toxic metals, solvents, gases, pesticides, and fibers — with exposure route, acute/chronic effects, and mnemonics. Built for CIH, maps directly onto CRSP and CRST hazard-ID domains too.
View reference → FIELD REFERENCE
Noise Dosimeter Setup: OSHA HC, OSHA PEL & ACGIH TLV
How to configure a 3M/Quest Edge 5 dosimeter for all three profiles at once — with a real setup screenshot and a real Criterion Level configuration error, annotated.
See the setup → FIELD REFERENCE
How to Apply A-Weighting: Octave-Band Table & Real Dose Examples
Frequency weighting explained, the real octave-band correction table, and a full worked multi-machine example — distance correction, source combination, and a real OSHA-vs-ACGIH dose comparison.
See the walkthrough → FIELD REFERENCE
Ear Anatomy & Industrial Hygiene: A Field Reference
Outer, middle, and inner ear anatomy mapped directly to conductive vs. sensorineural hearing loss, ototoxicants, the acoustic reflex, acoustic trauma vs. NIHL, and audiometric testing frequencies.
See the anatomy →
Master Every CIH Equation
The CIH exam gives you a bare equation sheet and an on-screen calculator — nothing else. The Equation Master is built around that exact reality, in three steps.
Base Math Theory & Calculator
Before the equations, the calculator itself. A sidebar walks through the underlying math — powers and repeated halving, square roots, logarithms, natural log, scientific notation — each with the exact keystrokes for the CIH-approved scientific calculator, plus a note on which equations actually use that skill.
Paired with a full working scientific calculator (MultiView, trig, logs, memory functions) built directly into the app, so you practice on the same interface you'll use on exam day.
Concept & Practice, Per Equation
Every formula on the exam gets its own Concept and Practice tab. Concept breaks the formula down variable by variable — Notation & Units, a plain-language Explanation, When to Use, and Key Concepts. Practice then drills it, so recognizing the formula and remembering what each letter stands for becomes automatic instead of something you're still working out mid-exam.
All 98 equations are organized into six categories — Radiation, Ventilation, Hood Airflow, Noise, Heat Stress, and Science & Statistics.
Equation Sheet + Calculator — the Exam, Simulated
The real CIH exam gives you a bare formula sheet with no notation help and no explanations — just the equations and constants. The app's Equation Sheet mode is built to match that exactly, paired with the same calculator. Practicing here isn't just equation review — it's a dry run of the actual exam-day interface, so nothing about the format is unfamiliar when it counts.
Try the CIH Equation Master Free
All 98 equations, worked practice problems, dimensional-analysis breakdowns, and a built-in scientific calculator.
Try Free — Radiation Category →No sign-up required
Already working toward CRSP or CRST instead?
SPEP's full CRSP and CRST question banks are live — 4,057+ blueprint-aligned questions, case-based scenarios, and adaptive weak-area tracking.
CIH Exam Prep — Frequently Asked Questions
Is the CIH practice question bank ready yet?
Not yet. SPEP already has full CRSP and CRST practice question banks built from real observed exam patterns. For CIH, SPEP is documenting a real, first-person exam journal as the founder studies and sits the exam himself — once he completes it, SPEP plans to build a CIH question bank the same way, based on what actually gets tested.
What is the CIH Equation Master, and is it free?
The CIH Equation Master is a standalone calculator and practice tool covering all 98 equations on the CIH exam, organized by category (Radiation, Ventilation, Hood Airflow, Noise, Heat Stress, and Science & Statistics). It includes a built-in scientific calculator, per-equation notation and practice, and an Equation Sheet mode that matches the bare formula sheet provided on the real exam. The Radiation category is free to try with no sign-up required.
How is CIH content different from the CRSP/CRST content on SPEP?
CRSP and CRST have complete, blueprint-aligned practice question banks built after the founder passed both exams. CIH is being built the opposite way, in public: the founder is documenting his own CIH study process as he goes, sharing reference guides and the Equation Master as he builds them, ahead of sitting the exam himself.
Is SPEP affiliated with BGC or ABIH?
No. SPEP (Safety Professional Exam Preparation) is an independent exam preparation resource and is not affiliated with, endorsed by, or connected to BGC (Board for Global EHS Credentialing), formerly ABIH.
Where should I start if I'm new to CIH exam prep?
Start with the CIH Exam Eligibility checklist to confirm you qualify, then the CIH Exam Journal to follow real chapter-by-chapter prep notes. If you're ready for equations, the CIH Equation Master's Radiation category is free to try immediately with no sign-up.