Understanding API 670 Standard

Devices

Portable balancer & Vibration analyzer Balanset-1A

$2,336.95 Izvorna cijena bila je: $2,336.95.$2,011.55Trenutna cijena je: $2,011.55.

Parts

Vibration sensor

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Parts

Optical Sensor (Laser Tachometer)

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Devices

Balanset-4

$8,049.74

Parts

Magnetic Stand Insize-60-kgf

$54.43

Parts

Reflective tape

$11.83

Devices

Dynamic balancer “Balanset-1A” OEM

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Definition: What is API 670?

API 670 (American Petroleum Institute Standard 670: “Machinery Protection Systems”) is the globally-recognized industry standard specifying minimum requirements for vibration, temperature, and position monitoring systems that provide automatic alarming and shutdown protection for critical rotating machinery in petroleum, chemical, and power generation industries. API 670 defines sensor types and quantities, alarm/trip setpoints, redundancy requirements, testing procedures, and system design criteria ensuring reliable machinery protection against catastrophic failures.

API 670 compliance is mandatory for most large turbomachinery (> 10,000 HP) in hydrocarbon service and is widely adopted as best practice even beyond petroleum industry. It represents the consensus industry standard for machinery protection, balancing safety and reliability with practical implementation.

Scope and Applicability

Covered Equipment

• Steam and gas turbines
• Centrifugal and axial compressors
• Centrifugal pumps in critical service
• Generators and motors > 10,000 HP
• Expanders and blowers
• Generally: critical turbomachinery in petroleum and power

When Required

• Equipment > 10,000 HP typically mandatory
• Critical service (no backup, high consequence)
• Contractual requirements
• Corporate standards
• Often applied voluntarily as best practice

Key Requirements

Radial Vibration Monitoring

• Sensors: XY proximity probe pairs at each bearing (4 probes minimum per bearing)
• Measurement: Shaft displacement relative to bearing
• Alarm: Typically 10-15 mils (250-380 µm) peak-to-peak
• Trip: Typically 25 mils (635 µm) peak-to-peak
• Response Time: < 1 second from trip to shutdown initiation

Axial Position Monitoring

• Sensors: 2 axial displacement probes (redundant)
• Purpose: Thrust bearing condition, axial rotor position
• Alarm/Trip: Set based on available axial clearance

Phase Reference (Keyphasor)

• Sensors: 2 keyphasor probes (redundant)
• Purpose: Once-per-revolution timing for phase and speed
• Requirement: Mandatory for complete rotor analysis

Bearing Temperature

• Sensors: 2 RTDs per bearing (redundant)
• Alarm: Typically 95-105°C
• Trip: Typically 110-120°C

Redundancy and Voting

Sensor Redundancy

• Minimum 2 sensors for each critical parameter
• Prevents single-point sensor failure
• Enables voting logic

Voting Logic

• 2-out-of-2 (AND): Both sensors must agree to trip
• 2-out-of-3: Any two of three sensors triggers action (preferred for critical)
• Purpose: Balance nuisance trip prevention with failure protection

Monitor Redundancy

• Dual monitor racks sometimes specified
• Independent power supplies
• Fail-safe design throughout

System Features

Required Functions

• Real-time displays of all parameters
• Alarm and trip functions with time delays
• Alarm acknowledgement and reset
• Bode and orbit plots
• Event recording
• Diagnostic software tools

Data Recording

• Continuous trending of all parameters
• Startup/shutdown transient capture
• Alarm event data
• Historical archiving

Testing Requirements

Factory Acceptance Test (FAT)

• Complete system tested before shipment
• All functions verified
• Calibration confirmed
• Documentation provided

Site Acceptance Test (SAT)

• After installation, full functional test
• Verify all sensor channels
• Test alarm and trip functions
• Validate against specifications

Periodic Testing

• Quarterly or annual functional tests
• Verify trip circuits functional
• Sensor calibration checks
• Documentation requirements

Recent Revisions

5th Edition (2014)

• Modernized for digital systems
• Enhanced cyber security requirements
• Updated sensor specifications
• Improved testing procedures
• Current version widely implemented

Related Standards

• API 617: Axial and centrifugal compressors
• API 610: Centrifugal pumps
• API 684: Rotor dynamics analysis
• ISO 7919: Shaft vibration limits
• ISO 10816: Bearing housing vibration limits

API 670 is the cornerstone standard for machinery protection systems in petroleum, chemical, and power industries. By specifying sensor configurations, redundancy, alarm/trip levels, and testing requirements, API 670 ensures consistent, reliable protection implementation across facilities worldwide, preventing catastrophic turbomachinery failures through proven monitoring and automatic shutdown capabilities.

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