Burner Management Systems: NFPA 85

Burner Management System (BMS) Overview

• The primary purpose of a BMS is to ensure the safe operation of burners and prevent hazardous situations during combustion processes.
• NFPA 85 outlines safety standards to minimize risks associated with boiler and combustion systems.

Communication with BMS

• Components that typically communicate with a BMS include:
  • Flame detection devices
  • Safety valves
  • Combustion air control systems
  • Fuel supply shutoff valves

Customization Options for BMS

• Factory Mutual (FM) allows operators and burner technicians to customize:
  • Control logic and safety protocols
  • User interfaces for monitoring and adjustments
  • Alarm settings tailored to specific operational needs

Key Functions of BMS

• A BMS plays a crucial role in monitoring and controlling combustion equipment to maintain safe operating conditions.
• It ensures that hazardous conditions, such as gas leaks or flame outages, are promptly addressed.

Programming Configuration

• Most BMS systems utilize a flexible programming configuration which supports various combustion management strategies and safety interlocks.

NFPA 85 Prevention Goals

• The NFPA 85 standard aims to prevent incidents like combustion explosions and emissions issues by implementing stringent BMS protocols.

Distinction of Programming Controllers

• Programming controllers are designed to perform complex safety logic functions, unlike primary controls, which typically focus on direct burner operation control.

Pre-Ignition Interlock Circuitry

• The purpose of pre-ignition interlock circuitry is to ensure that all safety checks are completed before allowing the ignition of the burner.

Transition to Electronic Programming Controllers

• Modern programming controllers have transitioned from electro-mechanical designs to electronic devices for improved reliability and responsiveness.

Purpose of Purge Proving Circuitry

• Purge proving circuitry ensures that the combustion chamber is clear of explosive gases before ignition begins.

Airflow Recognition for Pilot Burner

• The programming control must detect low airflow conditions to prevent pilot flame failure, which could lead to dangerous situations.

Firing Rate Management

• Programming controls manage burner firing rates more effectively than primary controls, allowing for smoother adjustments depending on demand.

Complexity of BMS Categories

• The most complex category of BMS involves systems that require advanced control strategies and integration of numerous safety features.

Timed Ignition Period in Primary Control

• The 'Timed Ignition Period' ensures that there is sufficient time for the burner to ignite safely within predetermined limits.

Importance of Flame Failure Response

• The 'Timed Flame Failure Response' function is essential to quickly shut down the system if a flame goes out unexpectedly, preventing fuel buildup.

CSA B149.3 Limits

• The CSA B149.3 standard restricts the 'Pilot Trial-for-Ignition Period' to prevent excessive risks during ignition attempts.

Flame Relay Components

• A simple flame relay typically does not include complex safety interlocks or advanced control features found in more sophisticated systems.

Risks of Excessive Ignition Timing

• If the 'Timed Main Flame Trial-for-Ignition Period' exceeds recommended limits, it may lead to increased risk of unsafe conditions, such as unburned fuel accumulation.

Test your knowledge on burner management systems which are dedicated to combustion safety and operator assistance in the starting and stopping of fuel preparation and burning. Learn about the components and safety controls involved in ensuring safe burner operation according to the NFPA 85 Boiler and Combustion Systems Hazard Code.