Frequently asked questions

Qualified people; specialist advice

  • Height safety
  • Rope access
  • Confined space and rescue

Call Height Dynamics on 07 3862 2533 with your technical questions

Rope Access

What is in a rope access kit?

There is a large variety of equipment that rope access technicians use in their rope access kit. Download our Rope Access Equipment List for an overview.

There you will find items that have become industry standards such as the Petzl ID Descender or the Petzl ASAP Lock through to as well as items that are less commonly used like the ISC D4 or the CT Sparrow.

If you are new to the Rope Access industry training in the correct use of this equipment and the techniques used are mandatory. Further information on our Rope Access training courses can be viewed on our website.

While the Rope Access Equipment List covers the basics it is no substitution for advice from specialist equipment suppliers. Contact Height Dynamics experienced sales team for more information.

Height Safety

Do lanyards need a shock absorber?

To meet AS/NZS 1891.1 2007, which is the standard that fall arrest lanyards are manufactured to, a lanyard must have either integral energy absorbing properties or a personal energy absorber attached to it. The energy absorber is tested to ensure that the force to the anchor point (and user) is no more than 6kN.

Even when using the “restraint technique” to prevent a fall from heights Section 5.2 of the Code of Practise* states that the restraint system (anchor, lanyard and harness) must conform with AS/NZS 1891 Industrial Fall-arrest Systems And Devices series.

*Download a copy of the Managing The Risk Of Falls At Workplaces Code Of Practice 2015 here

What fall arrest harness should I choose? 

compliance level fall arrest harness will have limited or no extra features while a specialty harness will have unique features to meet specific applications or non-standard environments.

To assist with your choice consider the following questions

  • What tasks do you need the harness to perform?
  • How often will you be using your harness?
  • Does the harness fit correctly?
  • What extra features do you require your harness to have?

For more information about fall arrest harnesses refer to our article Choosing a Fall Arrest Harness or contact our technical sales team.

What is the difference between fall arrest and fall restraint?

Simply put a fall arrest system will catch you if you fall, a fall restraint system will stop you from falling in the first place. The “restraint technique” still uses uses fall arrest rated equipment. However, it is used in a way that limits or restrains the user travelling to a position that free fall or fall arrest can occur.

Our article Fall Arrest vs Fall Restraint provides more information on using the "restraint technique"

How do I calculate fall clearance?

When working at height, knowing the required fall clearance is crucial to protecting yourself in case of a fall. The position of the anchor, the length and tear out distance of the fall arrest lanyard and the free fall distance are all factors that must be considered. There are three parts to the equation to work out the fall clearance that is required.Our article What is Fall Clearance provides detailed instructions on how to calculate fall clearance. Alternatively you may want to head to our web based Fall Clearance Calculator and have us do all the calculations for you.

What are the strength requirements for certified fall arrest anchors? 

A certified fall arrest anchor must meet the requirements of AS/NZS 1891.4 and the Work Health and Safety Regulation 2011.

To meet these requirements

  • The rating of the fall arrest anchor must be 15kN (approx 1500kg) for 1 person and 21kN (approx 2100kg) for 2 people.
  • The anchor must withstand this force in all directions in which the force could be applied.
  • A competent person must inspect and approve the anchor point before it is first used.
  • A competent person must assess the strength of the building or structure.

If any doubt exists in the structural adequacy of the anchorage, an engineer must make the assessment.

For more information contact Height Dynamics technical specialists

What's in a Roofers Kit?

A Roofers Kit is a compatible collection of height safety equipment designed to prevent falls whilst working on a roof. Basic components include a full body harness, rope (with adjuster and integral lanyard) plus anchor strap. Kit upgrades may include a temporary anchor, an additional shock-absorbing lanyard and extra carabiners. See Roofers Kit Guide > Shop Roof Work Collection >

How can I find a height safety "competent person"?

Engaging a "competent person" is a requirement under the Australian Height Safety Standard AS/NZS 1891.4 - especially when it comes to installing and/or first using height safety systems and equipment. However, height safety competency is not clearly defined in the industry and there is no formal licensing regime for height safety professionals in Australia. Your best strategy is to seek out a fully qualified height safety specialist with sufficient length and depth of experience plus a proven track-record of compliant installations. Then drill down on their skill level using our five levels of demonstrated height safety competency checklist >

Can I and/or should I ever work alone on a roof?

Should you ever work alone on a roof? The short answer is No. Working alone adds unnecessary risks and reduces your safety margin, leaving you vulnerable should anything go wrong. It's not good practice and is never something we would recommend.

Working alone on a roof is also strictly prohibited under Work Health & Safety Regulations whenever a fall arrest system is required to keep you safe. The need for a fall arrest harness system indicates that existing fall prevention controls alone are not enough to eliminate the risk of falling. And in the event of a fall, users will likely suffer physical injury. Which in turn raises the spectre of needing at least one suitably trained person on-hand to execute an emergency rescue plan. Of course, this cannot be done if you fall whilst working alone.

See Working Alone on a Roof for more details

Confined Space

Gas detector calibration vs Bump test. What’s the difference?

A gas detector calibration is more thorough and confirms the accuracy of gas detection. Bump tests just check the sensor and alarm actually work.

A bump test doesn’t tell you anything about the accuracy of the gas detector’s performance, but it does give you confidence that it is working and is therefore suitable for use.

The gas detector calibration process involves testing the gas detector’s sensors against a known calibration standard (i.e. the contents of your bottle of calibration gas), and adjusting the gas detector to correct for any inaccuracies.

How often should bump tests be carried out?

Best practice for a bump test is daily, and prior to use. Bump testing is the best way to make sure your gas detector actually works before you use it.

How often should gas detectors be calibrated?

Calibration frequencies differ between gas detectors and the manufacturer’s recommendation should be heeded. Height Dynamics calibrate all leading brands. Contact our team if you need help.

What are the characteristics of a confined space?

Under the Safe Work Australia model and Australian Work Health and Safety Regulation 5, a confined space must meet the following four criteria:

  1. Either fully or partially enclosed; and
  2. Not designed primarily for human occupation; and
  3. Designed to be at a normal atmospheric pressure; and
  4. Contains at least one of the following health and safety hazards:
    • an atmosphere with unsafe oxygen levels
    • a contaminant (gases, vapours, dusts) that may cause injury from fire or explosion
    • harmful concentrations of an airborne contaminant
    • the potential for engulfment

Note: It is possible for spaces that do not ordinarily qualify as confined to be temporarily rendered a "confined space" due to changes and/or additions made (such as adding a temporary wall or bringing contaminants into the space for storage). If so, you must treat these as you would any confined space.

See What is a Confined Space? for more details

What are common examples of confined spaces?

Common examples of confined spaces include storage tanks and bins, pressure vessels, pipes and boilers, sumps and pump hoppers, abandoned tunnels or shafts, degreasing pits, wet and dry wells, excavation holes and trenches, refrigeration units, tanks or vats, wheel motor housings, industrial silos and sewers. See What is a Confined Space? for more details

What do you need to work in a confined space?

To work in a confined space you must have three things:

  1. Confined Space Entry Permit: You cannot enter or work in a confined space without a permit. Confined Space Entry Permits must be completed by a competent person. To obtain such a permit, your site must be officially designated a confined space. All permit holders must also be sufficiently trained
  2. Confined Space Training: The completion of professional, industry-recognised confined space training is a pre-requisite to obtaining a permit to work in a confined space. This specialist training can typically be underatken with a relevant industry body or your local height safety specialist
  3. Confined Space Equipment: To enter and work in a confined space, you must have the specialist confined space equipment required to mitigate any health and safety risks associated with the space

See What is a Confined Space? for more details


How often should refresher training take place?

Competency maintenance is a requirement under the Australian Standard AS/NZS 1891.4. Appendix E4 states that;

"Persons should be reassessed, at appropriate intervals, to confirm ongoing competency relevant to their tasks associated with working in a fall risk environment, in particular persons required to perform emergency rescues need to be reassessed on an annual basis. A person should be retrained whenever they cannot demonstrate ongoing competency. The duration of retraining should be sufficient for the person to demonstrate the required competencies."

Height Dynamics recommendation for refresher training is 2-3 years. For workers not utilising the skills regularly it may be worth having the refresher at 1-2 years to ensure competency.

Our frequently asked questions page attempts to provide answers to common questions our customers are faced with when working at height or in confined spaces.

Naturally, given that workers encounter many height safety scenarios, this list is not exhaustive.

So if your question isn’t answered here, get in touch and someone from our team of height safety specialists will be happy to help.