Which Rectangular Rapid Flash Beacon (RRFB) flash pattern should I use?

This article explains how to choose the correct RRFB flash pattern when programming the Energy Management System (EMS) in your Carmanah RRFB system.

Product applicability

The following products are discussed in this article:

  • Legacy: R920 and SC315
  • E Series: R920-E
  • F Series: R920-F
  • G Series: SC315-G


The Energy Management System (EMS) is the main control board for your Carmanah Rectangular Rapid Flashing Beacon (RRFB) system. When you order your Carmanah system, nearly every EMS setting is preprogrammed at the factory for your specific location. There are also several settings that can be adjusted during and after installation. Please refer to the EMS sticker guide in your solar engine (E or F Series) or cabinet (G Series), or see the applicable manual here

Adjusting certain settings (such as LED intensity) may increase your system's energy load, making the beacon no longer sustainable. Refer to your user manual for guidance or contact Carmanah Product Support before attempting to change EMS settings.


One common user-adjustable setting for RRFBs is the flash pattern setting. As of February 2021, there are three flash patterns that can be used:

  • RFB: updated accuracy for wig-wag + simultaneous (WW+S) [latest]
  • RFB1: wig-wag + simultaneous (WW+S) 
  • RFB2:  WSDOT custom pattern for circular rapid flashing beacons

While both RFB and RFB1 are IA-21 compliant flash patterns, Carmanah began using RFB as the standard RRFB flash pattern starting 2020 Q1. Unless advised otherwise, any RRFBs ordered since 2020 Q1 should use the RFB flash pattern setting on the EMS.

For a replacement EMS, Carmanah will attempt to match the correct flash pattern based on your original order. For systems ordered before September 2014, you may have a legacy RRFB flash pattern that is no longer compliant under IA-21. This means that if you have a knockdown or require a replacement EMS for a system using the legacy wig-wag flash pattern, you will need to replace each system's EMS at that specific crossing. 


Here are some video examples showing legacy and current RRFB flash patterns. 

    Legacy wig-wag flash pattern Current IA-21wig-wag + simultaneous



    Shipment Date From Carmanah

    System Model

    Flash Pattern

    IA-21 Compliant

    Replacement EMS Flash Pattern Setting

    September 2014 or older




    Legacy wig-wag



    October 2014 –
    ~Q1 2020

    R920 / SC315 (legacy)







    ~Q1 2020 and newer







    ¹ These existing systems may remain operating until the end of their useful serviceable life. IA-21 stipulates the following:

    Existing RRFB units that use the flashing sequence that was specified in the Interim Approval 11 memorandum and a subsequent interpretation (the RRFB indication on the left-hand side emits two slow pulses of light after which the RRFB indication on the right-hand side emits four rapid pulses of light followed by one long pulse of light) should be reprogrammed to the flash pattern specified above in Condition 5b as part of a systematic upgrading process, such as when the units are serviced or when the existing signs are replaced.

    ² All systems at a crossing with this legacy version must be replaced with a new EMS when servicing. This will ensure these systems are updated to the IA-21 flash pattern specification.

    For more information on the RFB flash pattern update, please refer to this article