Crematory Smoke and Opacity Monitoring: Choosing the Right System

EMS Learning Center · Application Guide

Choosing a crematory smoke monitoring system starts with the information your operators and equipment controls need. Do you need a relay response when smoke reaches a selected level, continuous percent-opacity readings, or a system that meets a specified regulatory monitoring requirement?

The Guardian suits applications centered on smoke detection and relay response. The WatchDog 800 adds continuous opacity monitoring, a numerical opacity display and a recordable analog measurement signal for percent opacity.

This guide helps crematory and incinerator manufacturers and facility operators organize those requirements before selecting equipment.

When is smoke detection sufficient?

Smoke detection may be sufficient when the operating objective is to activate a relay at a selected smoke-opacity level, and the application does not require continuous numerical opacity measurement, a recorded measurement signal or a specified compliance-monitoring system.

The EMS Guardian detects smoke opacity across the process opening and activates relay contacts at the selected set point. Consider it when the equipment needs a straightforward smoke-detection signal for an alarm or a compatible control-system response.

The Guardian is a smoke opacity detector, not a continuous opacity monitor. Confirm that its detection function, mounting arrangement and relay interface fit the equipment and the facility’s requirements.

When do you need continuous opacity measurement?

Continuous opacity measurement is useful when operators need to see a numerical percent-opacity reading and follow how that reading changes during operation. It also supports applications that need a measurement signal sent to compatible controls or recording equipment.

The WatchDog 800 is a single-pass continuous opacity monitor. Along with its numerical display, it provides a 4–20 mA analog output and an alarm relay. The analog signal can be connected to compatible equipment for recording or trending; the required recorder or control-system input should be included in the installation review.

For a crematory or incinerator application, confirm the optical path, mounting positions, operating conditions and required outputs with EMS. The WatchDog 800 can also be evaluated for commercial boilers and other industrial process-monitoring applications.

Compare the EMS Guardian and WatchDog 800 side by side for a closer look at their functions, controls and outputs.

Check the permit and monitoring requirements first

A smoke-opacity alarm, a continuous process measurement and a specified regulatory monitoring system serve different needs. Continuous measurement alone does not establish compliance with a particular regulation.

If your installation requires 40 CFR Part 60, Appendix B, Performance Specification 1—Specifications and Test Procedures for Continuous Opacity Monitoring Systems in Stationary Sources, discuss the WatchDog PS-1 and the applicable installation, performance-testing and ongoing quality-assurance requirements with EMS.

Share the relevant permit language and equipment specifications before selecting a monitor. Confirm the applicable requirements with the facility’s responsible compliance personnel or permitting authority.

What should manufacturers and operators review?

• Purpose: identify whether you need smoke detection, continuous opacity readings, recording, process-control input or a specified compliance function.
• Stack and duct arrangement: provide the optical path, mounting-port details and whether multiple chambers discharge into a common stack.
• Operating conditions: describe exhaust temperature, expected contamination, ambient exposure and access for service.
• Electrical interface: confirm available power, relay requirements, analog inputs and signal scaling.
• Installation and support: plan access for alignment, cleaning, functional checks and maintenance.

For cremation and incinerator equipment manufacturers

Review monitoring requirements early in the equipment design. Share stack or duct drawings, controller input requirements, available power, expected quantities and project timing. Reviewing the monitor and controls together helps identify mounting and integration needs before production.

For facility operators replacing an existing detector

Provide the existing manufacturer and model, mounting photographs, dimensions and wiring information. A replacement should be checked for mechanical fit, electrical compatibility and the monitoring function required by the installation.

Plan for maintenance and service

Follow the selected instrument’s manual for inspection, cleaning, alignment and calibration procedures. Maintenance frequency should reflect the installation and its operating conditions.

EMS has manufactured and serviced opacity monitors since 1990. Review our opacity monitor service and support options and find current manuals and data sheets before planning installation or service.

Frequently asked questions

Is a smoke opacity detector the same as a continuous opacity monitor?

No. The Guardian focuses on smoke detection and relay response. The WatchDog 800 adds continuous percent-opacity measurement, a numerical display and a recordable analog signal.

Can the WatchDog 800 provide a record of opacity readings?

Its 4–20 mA output provides a signal that compatible external recording equipment can use. Confirm the recorder, input range and signal scaling when specifying the system.

Does every crematory need a PS-1 opacity monitor?

Select the system from the facility’s applicable permit and monitoring requirements. The fact that equipment serves a crematory or incinerator does not, by itself, identify the required monitor. Share those requirements with EMS for application review.