Sunday 28th Feb, 2021

BULKtalk: Engineering inconsistency

Steve Davis, Senior Bulk Handling Expert at Advisian, explores the ins and outs of formatting engineering documents and why consistency is key.

In recent months I have been involved in creating and reviewing many documents relating to various projects from around the globe. They are all in the English language, and they highlight that many of us, myself included, should take a step back and consider what we are circulating in text. This has particular impact if anything written down becomes part of a legal or commercial document.

English is a diverse language and is not everyone’s first language, but most of us would be using a Microsoft program such as Outlook, PowerPoint, Word or Excel to communicate. All of these have a variety of spelling and grammar checks that can be irritating but do save from making blatant errors in language.

Consistency is key – I have no problem with Australian or American English but not both forms in the same document. Center or centre, colour or color but not both. Do you put numerals in parentheses after numbers in words, and then randomly through a document at best? Don’t do this.

When referring to a specific person or term, be consistent. I have just read a document that refers to Principal, Company, Owner, Buyer, Purchaser and Operator, randomly capitalised and all meaning the same body. Also, Vendor, Seller, Contractor, Supplier.

For many years I have edited documents that become commercial when written into a contract. They are always peppered with a wide variety of modal verbs like can, could, may, might, will, should, shall, has to be, and must when something is expected to be supplied as part of the contract.

Until recently I believed ‘shall’ was the mandatory verb form, and all others implied various levels of ‘if you feel like it’. If you want to be correct legally and commercially today, I believe the only acceptable mandatory is ‘must’ – the shiploader must comply with AS4324.

Documents are the author’s and the company ‘face’, and poor-quality documents may be interpreted as an indicator of other quality and may even say something unintended. I often get documents with sections that are formatted in American, French or Spanish from where they were pasted into an English formatted document. Fonts change randomly in type and size, format changes from justified to left, centre and right, indents and bullets vary at every change, page and section numbering is incorrect, and headers that are different from page to page.

Do you check the abbreviations, glossary and references in your documents? I recently reviewed a mechanical specification that was obviously copied from another project ‘go-by’. All the references were to the other project, all the Standards were electrical, and at least 10 per cent were obsolete or incorrect. They were at least all for the correct region. To make it worse, the standard parts of the document, e.g. sections on corrosion protection, testing, packing and transport and others were not updated for the mechanical system.

Numbers and dates are another area that can be inconsistent in engineering documentation. Use 07/10/2020, 7-10-20, 10-07-20, or 7 October 2020 as you please, but use the same format throughout.  Use 2,000,000.00 or 2.000.000,00 or other numbering system but only one in a document If your estimate is accurate to ± 30 per cent, why are you telling me it is $3,267,452.19. Rounding to $3.27 million or even $3.3 million is good. Do you really mean the cost can be between $2.29 million and $4.25 million?

Does your project have many documents? Are they all formatted similarly? Is the information consistent throughout?

Units of measurement

Drawings and documents are how we communicate our requirements. It is no surprise then when we don’t get quite what we want.

I am not impressed by our use of measurement units in documents and drawings. In Australia we should be mostly using the (metric) SI measurement system, although we still have equipment that was built here in Imperial times and some that comes in from the US.

I am bilingual Imperial and Metric, but I hate documents and drawings that combine both unless necessary. Worse still are conversions and combinations. If unavoidable to have different dimension systems, make an appropriate note on the drawing.

Another problem stems from the computer assisted design (CAD) era. Take a conveyor that must be a set length overall and is typical trestle and gallery designs. Many drawings use CAD to divide the length into equal dimensions resulting in multiple gallery lengths that are 15,418 millimetres each, for example.

On a drawing board we would have automatically set the galleries at 15,500 millimetres, which is much easier to measure and set out, and with a single gallery having a make-up dimension. There are other examples of equispacing that just make it more difficult to measure and build things. I saw a drawing with a chute flange of 1000-millimetres-long annotated with “10 bolts, M16 equispaced”. At first glance that seems ok, 1000 / 10 = 100 mm spacing, but this doesn’t work. What spacing would you use?

Even when we get the dimensioning correct, I see many documents that define the units incorrectly, and often have two or more variations. First the table of SI units and non-SI units accepted for use with SI, and the prefixes.

The SI base units are now derived to an international standard. The definitions are certainly interesting and not what might be expected. A metre is defined as length of the path travelled by light in a vacuum in 1/299,792,458 of a second. Originally it was one ten millionth of the distance from the Earth’s pole to the equator, which is apparently not a stable dimension.

Regardless of language, the symbol is the same. The symbol km represents kilometre, kilomètre, chilometro and kilómetro. SI symbols express both singular and multiple. As an example, kilowatt is abbreviated kW, not KW and not kw. It is 100 kW and not 100 kWs or 100 kW’s. There is a space between the number and the symbol – 100 kW not 100kW. 25 C is 25 Coulombs not 25 degrees Celsius. SI symbols are always associated with numerals, 5 kg not five kg.

We weigh in tonnes, abbreviation t, not Mt (for metric ton), which is million tonnes. A million tonnes is not 1 mt, which would be 1 kg. We do not weigh in metric tons, there is no such unit. There are however short tons (2000 lb) and long tons (2240 lb) in the Imperial system.

Squares and cubes are m2 and m3, not m2 and m3. When combining units to get flow or similar the units are t/h, not tph or t/hr. Mt/a not Mtpy or Mtpa. kWh not kwhr or kWhrs. We should not measure anything in derived units, so pressure is measured in pascal.

There are many other rules, and some exceptions, but if you follow the above consistently your document will look significantly more professional.

PS; 500 ml is not a pint. A pint is 20 fluid ounces, except when you buy beer in the US, where it can be anything from 16 to 26 fl oz. Note that 20 fl oz is 568 ml, so we give away 15 per cent of most “pints” in an Australian bar.