POSISYS™ — UK Registered Trade Mark UK00004343983

The Complete
Ex01–04 Preparation System.

Stop studying blind. POSISYS™ combines adaptive question practice, full mock exams, daily mindfulness, a built-in Ready Reckoner and Darren's insider Pre-Study Guide — everything you need to walk into your five-day assessment prepared, not panicked.

£89 one-time · no subscription iOS · Android · Web Lifetime access · all updates included Built by an engineer who sat the exam

POSISYS™ Pro

Early Access Registration

£89 one-time

No subscription · No annual fee · All updates included

  • Adaptive Ex01–04 question bank
  • Full timed mock exam
  • Assessment countdown timer
  • Daily Calm & Focus sessions
  • Built-in Ready Reckoner
  • Pre-Study Guide included
Register Free — No Payment Now

Be first in line when we launch.

Engineers Have Been Flying Blind — Until Now

The Gas and Vapours Ex01–04 assessment is a five-day residential programme. Theory sessions. Four timed practicals. A multi-choice written exam. An enormous body of technical knowledge covering zones, protection concepts, cable glands, inspection grades, IS circuits, Zener barriers and more.

The cost of a single attempt runs from £790 to £1,500 before travel and accommodation. A resit costs £400 or more. Fail twice and you are looking at real money — and a real dent in your confidence and your career.

Until POSISYS™, there has been no dedicated preparation tool for this assessment. No app. No adaptive question bank. No mock exam. Engineers have been arriving at assessment centres having done nothing but read a textbook — and hoping for the best.

POSISYS™ is the answer to that. Not a quiz app dressed up as preparation. A complete preparation, confidence and mindset system — built by an engineer who has been exactly where you are.

£400+
Minimum cost of a single Ex01–04 resit — before travel or accommodation
5 Days
Residential assessment — theory, four practicals and a multi-choice exam
5 Yrs
Certificate validity — then a Refresh assessment is required
0
Dedicated mobile preparation apps that existed before POSISYS™

What POSISYS™ Is — and Is Not

POSISYS™ Is

  • A complete Ex01–04 preparation and confidence system
  • An adaptive question bank that learns what you do not know
  • A full timed mock exam built to mirror the real thing
  • A daily mindfulness tool for assessment anxiety
  • A built-in Ready Reckoner for key reference data
  • Darren's Pre-Study Guide, built directly into the app
  • An independent tool you own outright for £89
🚫

POSISYS™ Is Not

  • An official assessment centre or licensed CompEx product
  • A guarantee of passing — no one can promise that
  • A replacement for the five-day assessment itself
  • A subscription — you pay once and own it forever
  • Theory written by someone who read a textbook
🎯

Built For

  • Instrument, E&I and Electrical Engineers booked on Ex01–04
  • Engineers preparing for their five-year Refresh assessment
  • Anyone who has failed once and needs to nail the resit
  • Engineers in oil & gas, petrochemical, nuclear, LPG, refinery
  • Anyone who wants to arrive ready — not hoping

Six Systems. One App. Complete Preparation.

🧠

Adaptive Ex01–04 Question Bank

Hundreds of original example questions covering every topic in the Gas and Vapours assessment — zones, ATEX marking, protection concepts, cable glands, inspection grades, IS systems, Zener barriers, fault finding and more. The SM-2 spaced repetition algorithm tracks what you know and what you do not, surfacing weaker areas automatically. Every question is written and verified by Darren personally. Your revision time goes exactly where it is needed.

Core Feature
📝

Full Timed Mock Exam

Sit a complete mock assessment under timed conditions, built to mirror the format and pressure of the real thing. Review every answer with detailed explanations. Identify your weak areas before assessment day, not during it. The mock exam builds the mental stamina and familiarity with timed conditions that separates candidates who pass from those who freeze.

Core Feature
⏱️

Assessment Countdown Timer

Enter your assessment date and the app counts down every day. See precisely how many days you have and how your preparation is tracking against that deadline. Build a daily habit around your actual timeline — not a vague "I should probably revise" intention. The countdown makes your assessment real and your preparation purposeful.

Core Feature
🧘

Calm & Focus — Daily Mindfulness

Five minutes of guided mindfulness every day, designed for engineers — practical, no-nonsense and built around the specific anxiety that comes with a five-day residential assessment. Exam stress is real. It affects experienced, capable engineers just as much as anyone else. POSISYS™ includes this because it works. Start the day before your assessment date and continue through the five days themselves.

Core Feature
📐

Built-in Ready Reckoner

Every key reference table, classification and designation you need — gas groups, temperature classes, zone definitions, ATEX marking breakdowns, protection concept summaries, inspection grades, cable gland types — searchable and always with you. The Ready Reckoner is the reference tool Darren wishes had existed when he sat the assessment. Now it does.

Core Feature
📖

Pre-Study Guide Integration

Darren's complete Pre-Study Guide — written from real experience across multiple sittings of the Ex01–04 assessment — is built directly into the app. It tells you exactly what to study before you arrive at the assessment centre, in what order and what to prioritise. Written by someone who has been there. Not derived from a textbook. Not assembled from a course outline. From experience.

Core Feature

One Price. Own It Forever.

Coming Soon

POSISYS™ Refresh Pack

For engineers preparing for their five-year Refresh assessment.

£49

One-time payment  ·  No subscription

  • Refresh-specific question bank
  • Updated Ready Reckoner
  • Refresh assessment preparation guide
  • Calm & Focus sessions included

Register for early access and we will notify you when the Refresh Pack launches.

Be First. Pay Nothing Now.

POSISYS™ is in development. We are building it carefully — every question verified, every feature tested, every line of code reviewed. It will not be rushed.

Register your free early access now and you will:

  • Be the first to know the moment POSISYS™ launches
  • Be considered for the beta testing programme before public release
  • Receive Darren's free Pre-Study Guide PDF immediately
  • Receive the free Ready Reckoner PDF immediately
  • Get access to the free Readiness Snapshot diagnostic

No payment required now. No obligation. Just one email when we are ready — and you are first in line.

Register for Early Access

Free. No payment required. One email when we launch.

No spam. No third-party sharing. One email when POSISYS™ launches.

POSISYS™ FAQ

POSISYS™ is a purpose-built preparation and confidence system for the Gas and Vapours Ex01–04 hazardous area assessment. It combines an adaptive question bank, a full timed mock exam, an assessment countdown timer, daily five-minute mindfulness sessions, a built-in Ready Reckoner and Darren Emery's Pre-Study Guide — all in one app, available on iOS, Android and web.
No. POSISYS™ is an independent preparation tool built by Darren Emery M.Sc., a Senior Instrument Engineer and Technical Authority. It is not affiliated with, endorsed by or connected to any licensed assessment centre or the CompEx scheme. It is a study and confidence system — the assessment itself must be sat through an official licensed centre.
POSISYS™ Pro is £89 as a one-time payment. There is no subscription, no annual renewal and no hidden fees. All future updates are included at no extra charge. A separate Refresh Pack for five-year recertification will be available at £49. Early Access registrants are notified first and may be offered a launch price.
POSISYS™ will be available as a native iOS app, a native Android app and a web application. One purchase gives you access across all your devices. Your progress, question history and settings sync automatically between devices.
No. Every question in POSISYS™ is an original example question, written by Darren Emery and individually verified for technical accuracy. They are designed to test the same knowledge and concepts as the real assessment, but they are entirely original works. We respect intellectual property — and we invite correction of anything that needs amending, with a thank-you gift for any correction we use.
POSISYS™ is currently in development. We are building it carefully and correctly — not rushing it to market. Register your free Early Access now and you will be the first to know when it launches. You will also be considered for the beta testing programme if you would like to use the app before public release.