OXYL8 LEV Calculation App – Free Captor Hood and LEV Engineering Toolkit

Resource Summary

Free LEV Design and Assessment Tools for Apple and Android Devices

The OXYL8 LEV Calculation App is a free mobile application developed specifically for LEV professionals, occupational hygienists and engineers involved in the design, assessment and testing of Local Exhaust Ventilation systems.

Originally developed as a Captor Hood calculation tool using Fletcher’s Equations, the App has evolved into a practical field-based engineering toolkit incorporating several commonly used LEV calculations and benchmarking functions. The App is available free of charge for both Apple and Android devices.

The App includes tools for:

Captor Hood calculations
Effective captor distance calculations
Hood entry velocity calculations
Benchmark calculations
LVHV test-kit calculations
Velocity pressure (Vp) to transport velocity (Vel) calculations
LEV field assessment support

The App has become widely used throughout the LEV profession and is frequently utilised by:

LEV Designers
LEV Consultants
P601 TExT Engineers
Occupational Hygienists
Commissioning Engineers
LEV Trainers
Students undertaking BOHS qualifications
Duty Holders reviewing LEV performance

Source Document

Download information can be found in your phone App Store by typing in the search window “OXYL8”:

Source: OXYL8 Ltd

Document Type: Mobile Application

Platform: Apple iOS and Android

Cost: Free

Status: Current

Last reviewed by LEVCentral: June 2026

LEVCentral Expert Commentary

One of the challenges faced by LEV professionals is that many engineering calculations are undertaken away from the office.

Whether conducting a site survey, designing a new installation, commissioning a system or carrying out a Thorough Examination and Test (TExT), engineers often need rapid access to reliable calculations without returning to spreadsheets, textbooks or desktop software.

The OXYL8 App was developed to address this need.

The original module utilised Fletcher’s Equations to calculate the relationship between hood dimensions, face velocity and effective captor distance. The App supports calculations for:

Round hoods
Rectangular hoods
Slot hoods
Oval hoods

allowing engineers to quickly assess whether a proposed hood arrangement is likely to achieve effective contaminant capture.

Over time, additional modules have been added to support common LEV field calculations including benchmarking and velocity calculations. Recent versions also include LVHV-related calculation tools and enhanced benchmarking functions.

From a LEVCentral perspective, one of the most valuable aspects of the App is that it encourages engineers to think about capture performance rather than simply airflow.

This reflects an important occupational hygiene principle:

Airflow only becomes valuable when it effectively captures contaminants before they enter the worker’s breathing zone.

The App therefore supports better engineering decision-making whilst promoting good LEV design practice.

Key Learning Points

Effective Capture Is More Important Than Airflow Alone

The purpose of an LEV system is to capture contaminants before they reach the worker. Captor distance calculations help engineers understand whether this objective is likely to be achieved.

Fletcher’s Equations Remain Widely Used

The App uses Fletcher’s Equations to assist with the assessment and design of captor hoods and source-capture ventilation systems.

Field Calculations Improve Decision Making

Rapid access to engineering calculations can support better commissioning, troubleshooting and design decisions during site visits.

Benchmarking Supports Ongoing Performance Assessment

Benchmark calculations allow engineers to compare current system performance against historical reference values and identify deterioration over time.

Practical Tools Support Better LEV Outcomes

The App provides a convenient way of applying established engineering principles during real-world LEV assessments.

App Features

Captor Hood Calculator

Calculates hood entry velocity requirements and effective captor distances using Fletcher’s Equations. Supports round, rectangular, slot and oval hoods.

Benchmark Calculator

Provides support for benchmarking LEV system performance and monitoring changes over time.

LVHV Calculation Module

Supports calculations associated with Low Volume High Velocity systems used within a variety of industrial applications.

Velocity Pressure to Velocity Calculator

Assists engineers in converting measured velocity pressure values into transport velocity calculations whilst correcting for temperature and pressure effects.

Mobile LEV Engineering Reference Tool

Provides immediate access to commonly used LEV calculations whilst working in the field.

Why This Resource Matters

Many LEV calculations have traditionally been performed using spreadsheets, calculators or manual methods.

Whilst effective, these approaches are not always convenient when working on client sites, carrying out surveys or undertaking commissioning activities.

The OXYL8 App places commonly used LEV engineering tools directly into the hands of practitioners and helps bridge the gap between theoretical design principles and practical field application.

For many engineers, it has become part of their everyday LEV toolkit.

Further Resources

Recommended Learning

LEVCentral Observation

Many LEV practitioners carry airflow meters, manometers and anemometers. Increasingly, they also carry engineering calculation tools on their mobile phones.

The OXYL8 App demonstrates how digital tools can support better decision-making in the field by providing rapid access to proven LEV calculations.

Whilst no App can replace engineering judgement, it can make established design principles more accessible and easier to apply during everyday LEV work.

For many practitioners, it has become one of the most useful free LEV tools currently available.