By Grant Laidlaw

It is extremely important that a plant room logbook be implemented and is in fact a legal requirement.

Johan asks: Mr Grant, we are implementing plant room logbooks and were wondering what exactly is a plant room logbook and what type of information should be recorded in a logbook.

Hi Johan, When an inspector is issuing a certificate of conformance (CoC) he/she will definitely ask to see the plant room logbook. The logbook represents the most important record in the plant and as mentioned already, is a requirement for every plant.

The log book is a very valuable tool when used correctly and acts as a two-way communication record. All technicians should be sure to read it at the beginning of their work and make careful notes during, and on completion of work.

This is very important. As an example, you are looking for a leak on a system and have left the system on a vacuum test overnight. During the night the user notices that the plant is not running and looks in the logbook. As you did not record that you have the plant on vacuum test he attempts to start the plant and as a result the compressor suffers damage.

You are now liable for the repair as you:

  1. failed to lock out the electrical supply
  2. failed to inform the user and
  3. failed to record that the plant is under vacuum test and should not be started.

The logbook is a communication tool, a record and in addition can be used for evidence if required.

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The responsible person/contractor shall ensure that the logbook is kept accessible in the plant for at least three years after the last entry is made and shall produce the logbook for examination upon the request of an inspector and, where an electronic log is kept by the user, the user shall retain the electronic log or hard copies for at least three years.

Here are some recommendations in ensuring good quality information is gathered and recorded in the logbooks and in the plant files.

  • Logbooks must be “hard bound” and all the pages must be correctly dated and numbered.
  • Logbooks must be kept in a clean and safe location.
  • It is not acceptable to have logbook pages missing or torn.
  • All logbooks must be kept for at least three (3) years on site in the responsible person’s office or another safe location.
  • All persons who write in the logbook must have their full name written and a sample of their signature and initials on the inside cover of the logbook.

Every person who writes in the logbook must either sign or initial their recorded information at the end of their work. No space should be permitted between their signature and the end of the page or portion of the page dedicated to their shift.

“The logbook represents the most important record in the plant.”

The person in charge of the plant must either sign or initial every page at the end of each day to indicate that he/she has read the logbook. The person in charge may issue orders and make notes or indicate a place where orders may be found with respect to anything that is recorded in the logbook.

Proper log-keeping

There is a long list of the types of entries that are required to be in the plant log. This list can be summed up as, “all the significant events affecting the plant equipment during the shift and the time that the event occurred.”

The list can be summarised as follows:

  • Operational details of work and equipment status
  • Maintenance to any equipment that is part of the plant
  • Refrigerant use
  • Leak testing
  • Break downs
  • Emergencies
  • Repairs
  • Incidents
  • Work done or work in progress
  • Notification of outstanding issues at hand
  • Expected operational matters
  • Tests, inspections, audits, emergencies
  • Lock-outs, tag-outs, equipment standby or equipment under repair
  • Contractors on site, visitors, security and others in or about the plant premises
  • Attach sketches or other relevant information that may help in the details of your reporting
  • If external contractors are on site, ensure to record all of their names and trade and the reason for their presence in the plant
  • Ensure that all permit numbers are recorded particularly with respect to boiler and pressure vessel repairs, installations, welding, hot work permits, testing, gas work, safety devices, controls and instrumentation
  • Ensure that no UNAUTHORISED persons are permitted on plant premises and record any such event if you are unsure of someone’s function
  • Communicate all your reporting verbally to the client and advise colleagues to read the logbook before they take over any of the work
  • It is unacceptable to write foul and abusive language in the logbook and it is unethical to conduct personal vendettas and record any information detrimental to the integrity and good conduct of persons in the plant.

Ensuring that logbooks are properly kept and the information in the logbooks is clear and precise will contribute to the excellence of safe and effective plant operation by keeping good and valuable information that may be found to be very useful someday when you least expect it.

Johan, thank you for the question, I hope that this helps you moving forward. Logbooks are a very important technical aspect in the refrigeration and air conditioning industry often ignored.

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Justice asks: Mr Grant, What is the correct angle for a drill bit for steel to be sharpened to and are there different angles for drills to be sharpened for different uses?

Hi Justice, yes, there are different angles one should use when sharpening a drill. The angle that you should use depends upon the material that you are drilling into. When a drill is dull or chipped, sharpening is done to the point only. There are three aspects that must be taken into consideration when sharpening a drill, namely:

  • Lip-clearance angle
  • Even length and degrees of cutting edges
  • Point angle

It is the point angle that your question refers to, but consideration should also be given to the lip clearance angle.

The point angle for general work is at an included angle of 118 degrees.

Point and Lip Clearance Angles. Image supplied

Point and Lip Clearance Angles. Image supplied

Like single point cutting tools, the only part of the cutting tool to come in contact with the material machined, is the cutting edge.

Lip clearances must therefore be ground to the point of the drill to ensure that only the cutting edge comes in contact with the material, thus preventing the rest of the drill to rub against the material. You can see the lip clearance angle in the sketch.

The table included here gives you an indication of the point angle and the lip clearance angle that should be used for for drilling various materials.

Thank you for the question Justice, the sharpening of drill bits requires some practice but this is a skill all technicians should master.

Thank you for all your questions. Send your problems (and sometimes your creative solutions) to with ‘Solutions Page’ in the subject line. You may include pictures.


  1. ACRA
  2. SANS 10147

About Grant Laidlaw

Grant Laidlaw

Grant Laidlaw is currently the owner of the Air Conditioning and Refrigeration Academy (ACRA) in Edenvale. He holds a Bachelor of Business Administration and an associate degree in educational administration. He has a National Technical Diploma and completed an apprenticeship with Transnet. He has dual-trades status: refrigeration and electrical. He has been involved with SAIRAC for over two decades and served on the Johannesburg committee as chairman and was also president between 2015 and 2018. Currently he is the SAIRAC national treasurer.w

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