Opacity Monitor Learning Center
Industrial Opacity Monitoring Resources
Practical resources for understanding, selecting and maintaining industrial opacity monitors. Explore measurement fundamentals, compare single-pass and double-pass systems, review EPA PS-1 information, and find EMS manuals, forms and technical resources.
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Featured Opacity Monitor Guides
Learn what continuous opacity monitors measure, why your application may need one and how EPA PS-1 requirements fit. Then compare optical arrangements and use the selection guide to match a monitor to your permit, process and installation.
What Is a Continuous Opacity Monitor?
See how a light source, measurement path, detector and controller produce a continuous opacity reading—and why zero, span, alignment and clean optics matter.
Why Do I Need a Continuous Opacity Monitor?
Explore crematory smoke monitoring, boiler applications, process information and service planning, and distinguish operational needs from permit requirements.
EPA PS-1 Opacity Monitoring Requirements Explained
Understand applicability, installation and initial performance testing, plus the distinction between PS-1 and ongoing Procedure 3 quality assurance.
ASTM D6216 Opacity Monitor Requirements Explained
Learn how manufacturer certification supports continuous opacity monitoring, how ASTM D6216 relates to EPA PS-1, and what documentation to request.
Single-Pass vs. Double-Pass
Compare the two optical arrangements, understand how light travels through each system and learn which application and compliance questions should guide selection.
Choose the Right Opacity Monitor
Use permit requirements, optical path, process conditions, outputs, alarms, calibration and service needs to identify the appropriate type of monitor.
Compare Opacity Monitoring Systems
EMS WatchDog vs. WatchDog PS-1
Compare controllers, calibration features, relays, outputs and application requirements to select the right configuration for your installation.
EMS Guardian vs. WatchDog 800
Compare smoke-opacity detection with continuous opacity monitoring, including alarm relays, recordable outputs, calibration and application needs.
Industrial Opacity and Dust Monitors
Compare the standard EMS WatchDog opacity monitor, WatchDog 800, WatchDog PS-1 and Guardian by optical arrangement, application, path length, outputs and compliance capabilities.
EPA PS-1 Continuous Opacity Monitoring
Review EMS systems for applications requiring U.S. EPA 40 CFR Part 60, Appendix B, Performance Specification 1. Explore the EMS WatchDog PS-1 opacity monitor.
Review EMS EPA PS-1 opacity monitoring systems
Read the official EPA Performance Specification 1
Application-Specific Opacity Monitoring Guides
Opacity-monitoring needs vary by process, permit and purpose. This section will expand as EMS publishes guidance for specific industries, equipment and operating conditions.
Crematory Smoke and Opacity Monitoring: Choosing the Right System
Learn when smoke detection and relay response fit the application, when continuous opacity readings and a recordable signal are needed, and what to review before selecting a system for cremation or incinerator equipment.
Smoke Opacity Detector for Crematories & Incinerators
Review selectable alarm settings, optical-path requirements and installation considerations for smoke-opacity detection on cremation equipment and industrial incinerators.
Explore the EMS Guardian smoke opacity detector
- Boilers and power generation
- Cement and aggregate processing
- Paper mills
- Baghouses and ESPs
- Duct and exhaust monitoring
- Process-control applications
Documents, Service and Technical Resources
Manuals, Data Sheets and Forms
Find current EMS manuals, data sheets, brochures, dimension sheets and service forms.
Service, Audits and Certification
Review startup, certification, quarterly-audit, field-service and factory-service support for EMS opacity monitors.
Neutral-Density Filter Certification
Find audit-filter certification information and support for periodic opacity-monitor quality-assurance checks.
Rosemount OPM Support
Learn about EMS replacement parts, repair service and direct replacements for Rosemount OPM 3000, OPM 4000 and OPM 4001 opacity monitors.
Need Help Selecting an Opacity Monitor?
Send EMS your permit language, process description, stack or duct dimensions, temperature range, mounting details and required outputs. We can help identify the appropriate monitoring system and supporting services for your application.
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Monitoring requirements depend on the facility permit and applicable federal, state and local rules. Confirm regulatory requirements with the appropriate permitting authority.