Knowledge Base

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October – Loss Prevention Guide

October – Loss Prevention Guide

Do not ignore the detail – Be aware at all times!

We have all been there. You are tired, you were working yesterday and you are back on a job today or, one of your dear children kept you awake all night or, your boss has failed to recognise just how hard you work. There are dozens of reasons why you might not feel at your very best when faced with another cargo inspection.

But, you are an APCS Qualified and professional Petroleum Cargo Surveyor and your integrity matters. Your reputation is everything. So, let’s look at a few things that could seriously go wrong if you don’t keep your eye on the ball.

Note : If you are seriously too tired to conduct a cargo survey safely then don’t do it. Hand the job over to a colleague and then, perhaps join him when you are rested. Your safety is important, do not take risks.

Your instructions are to survey the loading of 30,000 m³ of Jet A1 kerosene to a ship at the terminal jetty. Fortunately for you, the cargo is to be loaded from a single shore tank. Let’s assume the ships tanks are suitable to receive Jet A1 and the lab results indicate the product to be on spec (we will discuss quality issues in future articles).

In this article we will concentrate on inspection details that could seriously effect the QUANTITY delivered.

 

Sampling and Density/ Specific Gravity

We all know that correctly sampling just one shore tank can be a laborious task. Sampling several shore tanks is simply hard work but, believe me, it is one of the most important activities of your cargo inspection. If you do not sample the product correctly you are wasting your time and the time, and money, of everyone else. There are no shortcuts – always draw your samples correctly. All Petroleum Cargo Surveyors should be conversant with API MPMS Chapter 8.1 Standard Practice for Manual Sampling of Petroleum and Petroleum Products.

To sample a product you must understand its characteristics, its industrial use, how it arrived in the tank you are sampling, and the volume of product in the tank.

For this product you will be using a dedicated Jet A1 sampler (no other will do), and all parts of the sampler will be clean and that includes the cord or the chain. In fact, especially the cord or the chain. You will be using new, clear glass, approved sample bottles. You will be aware of what levels you must take your samples at based on the volume of product in the tank and, you will be aware of any reason why you need to take special care of product layering, etc. If you take your samples all from the upper level, you risk the product density being assessed as too light. Conversely, all samples drawn from a lower level could show the product density to be too heavy.

But, why is that such a problem? Lets take a look:

 

Product GOV

Temp °C

Density @ 15°C

VCF

Metric Tons (vac)

30000

28.0

0.8015

0.9879

23754.056

30000

28.0

0.8010

0.9879

23739.237

Difference

0.0005

14.819

Using a theoretical product value of $700/ metric ton we can see that your lack of attention to sampling detail could cost your client $10,373 and the product has not even left the shore tank yet!

 

Temperature

In a similar way to the need to correctly sample the shore tank, obtaining accurate and representative product temperatures is vitally important. In fact, inaccurate temperature measurement is the single most cause of apparent (paper) loss of cargo.

Readers should also see our former article Improve Accuracy – Or Lose Your Job!

To summarise;

  • Where possible, always use your own temperature measuring device
  • Where possible, always use a portable electronic thermometer (PET)
  • Always take temperatures, strictly, in accordance with API MPMS Chapter 7
  • Never trust any device that is unknown to you and/or you have no proof of its accuracy 

Using the same example we used for difference of density, lets see how a lack of attention to accurate temperature determination can effect your client:

 

Product GOV

Temp °C

Density @ 15°C

VCF

Metric Tons (vac)

30000

26.0

0.8015

0.9898

23799.741

30000

28.0

0.8015

0.9879

23754.056

Difference

2.0

0.0000

45.685

Using a theoretical product value of $700/ metric ton we can see that your lack of attention to temperature detail could cost your client $31,980

 

Tank Gauging

API MPMS Chapter 3.1a details the procedure and techniques associated with manual tank gauging of petroleum and petroleum products and I do not intend to duplicate those here.

In addition to Chapter 3.1a I advise the following:

Wherever possible gauge tanks yourself and using your own gauging equipment.

Never trust any equipment that is not yours and cannot be proven to be entirely accurate.

Always, even in the finest of weather conditions, take the same measurement at least twice.

Be especially aware of:

Allowing the measuring tape to be slackened during a sounding (innage). The tape must be kept taught by the weight of the bob. Even a split second when a tape is allowed to go slack can give as much as 1-2cm inaccuracy (oil volume greater than it should be).

Conversely, when the measuring tape bob does not touch the true bottom or the datum plate then an inaccuracy will occur.

Always be aware of the tank reference height (from the tank calibration table) and ensure that your measured height is the same. If you are obliged to use the terminal’s gauging tape, take your time to first check it out for anything that may alert you to it’s inaccuracy. These could be:

 

Bob and Tape for Tank Calibration

Photo courtesy of Mr Paul Warbroek – Tanido B.V.

 

a) A sounding bob that does not match the tape. Measure the bob and tape to ensure accuracy

b) Look for any sign of tampering. Is a section of the tape missing and cleverly rejoined?

c) Do check the entire length of the tape and not just the first few meters (feet).

d) Is the tape kinked or buckled? If it is, don’t use it.

Finally, if you are not the person gauging the tank but you are there witnessing the process, be sure you look carefully at the gauger’s technique and double check the measurements. Do NOT just write down what the gauger calls out.

 

Tank Calibration Tables

How can you be entirely sure that a calibration table is the official one for the given tank. Well, I’m not entirely sure you can. People can be very clever where money is the motivation. But, there are a number of checks you can make to unnerve a scoundrel and, at least, protect yourself.

Check the table (book) for any loose pages or pages that have been fixed back in. Make sure these pages are the originals, the same paper and print as the others, the same colour and age as the entire book.

Check the Calibration Certificate and make note of the relevant details. Look also at the calibration date. A book that is 10 years old (for example) should raise suspicion if it looks new.

Never use a book where the print has been ‘improved by pen’ because the original print is worn.

Never use an extract of a calibration table that is used to ‘preserve the condition of the original book’.

Always, double check, and check again, the data you extract from the tables.

 

Finally, most of you guys now carry smart phones or tablets. Where it is permitted and safe to do so, take photograph copies of the calibration table to include, the front cover, the calibration certificate, applicable measurement corrections, and the pages that you have used to assess the volumes.

Phew, I think that is enough for this article and we have only covered the measurement of a single shore tank! Seriously, it doesn’t matter how often you have done the job or how tired you might be, it is the attention to the detail that makes you a true professional.

None of us know it all and the above article certainly does not cover all eventualities.

If you can think of other Loss Prevention procedures or techniques then why not share them with others on the APCS Forum or, write an article as a guest author. We will be glad to publish it with, or without, full credit to you or your company – as you wish.