Black Square Engineering have a history of designing and certifying all sort of lifting gear, to a wide range of Australian and International Standards including;
Swivels
Bull horns
Spreader bars and lifting beams
Pad eyes and lifting lugs
Jibs
C Hooks
Lifting frames
Man baskets
Equipment baskets
Lifting skids and supports
Strong backs
AS 1418.1 - 2002 Cranes, Hoists and Winches - General Requirements (and others in this set)
API 8C Ed. 5 (2012) Drilling and production lifting equipment (PSL 1 & PSL 2)
In this post we will talk specifically about AS 4991 - lifting devices as it is one of the standards we use most commonly. AS 4991 - lifting devices (Section 12) gives 2 methods to certify lifting equipment as detailed below:
Proof Load Testing
This method utilises a variable scale:
1. Up to a 10 t Working Load Limit (WLL) is a 2x WLL (0 - 20t)
2. From 10t to 160 t a test of 1.04 x WLL + 9.6 (20 – 176 t)
3. Above 160 t requires a 1.1 x WLL (176 t + )
To pass the test each device must hold the load for at least 1 minute and must not have any permanent set deflection exceeding 0.25% and all testing needs to complete as per AS 17025 General requirements for the competence of testing and calibration laboratories.
Following the proof test the lifting device is to receive adequate Non-Destructive Examination and Testing (NDE AKA. NDT) to check for evidence of flaws or defects.
Due to the potential cost and safety implications if a proof test fails, its recommended that lifting equipment is theoretically analysis before proof testing to identify any potential design flaws. However, this analysis can be a lot less rigorous then that be carried out if performing certification by engineering analysis (the second method).
Engineering Analysis
The second method is certification by engineering analysis. This method requires that the design undergoes analysis and certification by a third party and that the manufactured lifting device is subject to a test regime that includes:
Material identification
NDE of welds, Castings and other potential points of failure (as specified by the designer or Competent person)
Some specialised equipment may still require reduced proof load tests or alternative testing to prove the lifting device is fit for service.
Which Method of Lifting Equipment Certification is Best?
The best method of certification really depends on your specific requirements for example:
Is it’s a one of device or something that will be serially manufactured? Serially manufactured equipment generally asks for a more optimised design to bring down production costs, leading to certification by design to be the preferred method.
What is the size, WLL and type of equipment it is designed to lift? How accessible is suitable test equipment? Lifting devices designed to lift large, awkward or heavy equipment may require specialised equipment to be developed or procured to complete testing which can significantly increase the cost.
Is it an existing lifting device that has been in service for some time without material traceability or design documentation? Old or existing equipment without design of manufacturing documentation is generally easier to certify via testing. Removing the need for reverse engineering and material testing.
How complex are the restraint mechanisms used; is friction, magnetic or vacuum gripping used? These mechanisms may still require type testing or proof load testing if certifying by engineering analysis.
Is the lifting equipment going to be subject to a high number of load cycles? Proof load testing doesn’t take into account failure by fatigue so should not be used where fatigue may be an issue.
Recently, we were approached by a client that operates an aging production plant. It had come to their attention that that they had a number (approx. 20) of small lifting beams, frames and attachments around their plant that did not have any certification. The lifting devices where used for several different applications from holding bulky bags to positioning specialised equipment and ranged in WLL from 1 to 5 t.
As there was no design or manufacture documentation available for the lifting devices it was decided that proof load testing would be the best way to certify them. All the lifting equipment was proof tested by our engineer at the clients site using BSQE’s Load cells and equipment already available on site, allowing all the lifting equipment to be certified quickly with minimal interruption to production.
If you require any assistance certifying your lifting equipment via either method don’t hesitate to contact Black Square Engineering on 07 3188 0455 for our Brisbane based office or 07 4548 0686 for our Toowoomba office.
All our works meet the Professional Engineers Act (RPEQ) and we have access to and utilise the best engineering tools to find the best solution for your problem including;
First principles engineering analysis
Finite Element Analysis (FEA)
Load cells (up to 200T)
Tensile Test Machines (up to 200t)
Accelerometers and data recorders
Note: The Information summarised in this article is to be used as a guide only. Please refer to the relevant standards for exact requirements.