Made to Measure

Global BW - World Horizon Issue 02/2014

28 February 2014


Singapore will be the world’s first port mandating the use of mass flow metering (MFM) systems to measure fuel oil bunkering, announced the Maritime and Port Authority of Singapore (MPA) recently.

With 95% of the world’s shipping fleet still running on heavy fuel oil (HFO), this regulation will help to improve the accuracy and efficiency of bunkering operations. It will come into force in two stages. From 1 January 2015, new bunker tankers applying for Habour Craft (Bunker Tanker) license will have to be fitted with an MPA-approved MFM system. And from 1 January 2017, all existing bunker tankers are also required to use MFM systems for HFO bunkering in Singapore.

Singapore is the world’s top bunkering port by sales with 42.7 million tonnes delivered in 2013. Yet there continue to be reliability issues, with more than 80 cases of bunker disputes reported in the past 24 months. Through this regulation, the Singapore government is signaling a strong intent to safeguard the reputation of its ports and maintain its leadership in bunkering.


Bunker disputes can arise because of the complex physical characteristics of heavy fuel oil (HFO) and the different readings needed to confirm the weight of bunkers delivered.

Mass is a key determinant of calorific content given a particular fuel type, and is the main concern of ship operators. Bunkers are thus transacted by mass – but it is difficult to measure directly and is often calculated from a combination of volume, density and temperature measurements. The number of factors in play creates many opportunities for bunker sales to be inaccurately reflected, either accidentally or deliberately.

Moreover because HFO is a viscous fluid, if an excessive amount of entrained air is trapped within, it can “foam” and lead to inaccurate volume measurements. This opens up the opportunity for some bunker companies to inject air into the bunker while it is pumped into the ship’s tank, creating an elevated volumetric reading. The technique, also known as the “Cappuccino Effect”, is a longstanding issue plaguing the maritime industry.


Shipping Companies often engage independent surveyors to take readings from the tanks of the ship and bunker barge prior to and after the bunkering process. This is complemented by a continuous sample of the bunker taken during refueling operations, which is sent to a class society for testing. All of these precautions help to confirm the measurements and ultimately verify the weight of bunkers purchased.

In addition, ship operators will sometimes keep vessels that do not need to sail urgently in port for 24 hours after bunkering. This allows the bunker foams to settle and negates the “Cappuccino Effect”.


Mandatory mass flow metering will allow the maritime industry to have greater trust in the readings and measurements provided by bunkering companies, simplifying the process and increasing bunkering efficiencies as well as safety aboard. An approved MFM system can save 2 to 3 hours per bunkering operation in reduced measurement times alone.

Green Marine Capital’s portfolio company Ascenz is working with MPA to deliver MFM solutions and the company is well positioned to support this initiative. In addition to monitoring bunker transfers, Ascenz also offers MFM systems that track bunker consumption in real-time. More than 180 vessels have already paired up the Ascenz controller with their MFM devices.

Kevin Knott, Senior Manager at BW LPG, said “It’s a clear step forward. As a procurer of bunkers, we’d like it to be exactly the same as when you are taking your car to the petrol station. You know exactly how much you are getting for the amount that you are paying, and you know it is of a certain quality. That’s how it should be.”