Site Specific Assessment and Class Approval for Jack up Rigs

When it comes to safety for Jack Ups, there is a rigorous process in place including International Bodies (International Codes), Class Societies (Class Rules), National Legislation (Shelf States), and National Maritime Legislation (Flag States). Although they don’t require a flag, having one enables them to move freely across international waters. When this is planned, the Maritime Authority regulations must be adhered to according to the Flag State (the country whose flag they are flying).

Normally, each drilling unit will be registered with a Flag State Governmental Administration. Essentially, the role of this administration is to set the requirements for each registering unit and these requirements generally follow the lead of the International Maritime Organization (IMO) since these are internally-agreed suggestions. More recently, the responsibility of verifying compliance has been awarded to classification societies and they also issue Marpol certificates, Loadline, and Tonnage.

Moving away from the flag, there are some governments who also request all drilling units to adhere to their own safety regulations when working in their waters. For example, the United Kingdom has a Health and Safety Offshore Division which ensures the safety of all drilling equipment in UK waters.

In terms of classification societies, these are largely independent and have no relation to any other party and this is important because their sole priority is the quality of the Jack Ups. In addition to authorities, these societies could be the owners, insurance underwriters, charterers, sub-contractors, building yards, and finance institutions.

Figure 1 - Jack up Rigs in a Shipyard (, 2018)

Figure 1 – Jack up Rigs in a Shipyard (, 2013)

Classification Societies

With regulations and safety laws now introduced, there needs to be someone checking that every company is meeting the demands and this is the role of classification societies. During both design and construction, they will pay particular attention to quality and safety not only for the unit but the environment and personnel too. With each society, you will find different requirements whether it is Lloyds Register, American Bureau of Shipping (ABS), or Det Norske Veritas. This being said, many regulations have been set at a minimum by the International Association of Classification Societies to ensure a minimum quality.

Just like with ships, the rules of classification societies must be met by Jack Up drilling units. When a certificate is awarded, it shows that the unit is compliant with the regulations as well as meeting the minimum industry standard for both mechanical and structural fitness. After the first test, there are normally regular checks thereafter to ensure the unit remains compliant moving forward.

So what do classification societies look for? In truth, there are a number of categories included in every check including structural strength, legs, welding, materials, spud cans, superstructures, and that the Jack Up hull won’t succumb to corrosion. Furthermore, the unit needs to be able to survive in different environments including elevated operations, preloading and jacking, storm survival, etc. In each test, similar grounds will be used to test design such as water depth, hull weight, and environmental conditions depending on what is presented in the manual of the rig. Despite the many inclusions, safety and capacity of the foundation is omitted from these tests. During the approval testing, the owner will also take responsibility for the operation of the Jack Up unit.

Figure 2 - A Jack Up Rig Operating in Hash Environment (, 2018)

Figure 2 – Maersk Jack Up Rig Operating in Hash Environment (, 2018)

Naturally, Jack Up units should be mobile since they need to be able to work all over the world. Therefore, there isn’t one specific geographical location used in the rules and the units won’t be judged by one environment or set of conditions. After the unit has been manufactured, the designer and owner will note for which conditions the unit has been designed; this is known as the design criteria and theoretical operating envelope. To be successful, the designer and owner must ensure they meet the regulations of this particular envelope.

As you may know, Jack Up units will generally have both an afloat mode as well as a jacked up mode and this will be tested and analyzed during the process. When in the afloat mode, the leg structures will be checked for roll characteristics as well as gravity bending moment; once again, there will be a focus on storm conditions. For all new Jack Ups, fatigue analysis is also required alongside global structural analysis. Interestingly, many of the regulations were originally derived from the same rules for ships; over time, this has been optimized and adjusted wherever necessary. In addition to this, the common practices were also adjusted such as drilling operations, electrical equipment, fire safety systems, and high-pressure piping systems.

In afloat conditions, Jack Ups have a stability criteria that include the lowering of leg structures. In total, there are two main specified criteria; damage stability and intact stability. Whenever a Jack Up unit has met the minimum standards laid out, this doesn’t necessarily mean that they can operate in every area. Often, the owner will have to take into account the water depth of the water in which they plan to operate in addition to climatic, geotechnical, environmental, and seismic conditions. As a result, there is now a standard called the Society of Naval Architects and Marine Engineers (SNAME) T&R Bulletin 5-5a Guideline for Site Specific Assessment of Mobile Drilling Units; this is now widely used as a guide before performing the appropriate assessment.

Site Specific Assessment

As mentioned previously, Shelf State Legislation is important because each country will lay out their regulations for all those planning to operate Jack Up machinery. Nowadays, most countries are well-regulated and the legislations are vast but there are still some countries who haven’t quite reached this level. In these countries, the oil companies themselves, along with the owners, are responsible for defining their own documentation. As well as referring to their own regulations, they can also follow international guidelines such as those in ‘Recommended Practice’ within the Specific Assessment of Mobile Jack Up Units and this is issued on behalf of the Society of Naval Architects and Marine Engineers (SNAME).

Just as the name suggests, this evaluation will look at just how capable a Jack Up is within a particular location. Normally, the owner of the rig will be provided with the environmental conditions within this region and they then need to prove that their equipment is capable of handling said conditions. In today’s world, most of the large oil companies will have their own criteria alongside the SNAME RP. Ultimately, the SNAME RP is in place so that all Jack Up operations are documented in their global structure strength and foundation capacities. If the soil conditions, rig loads, and actual environment condition fall well within the range of acceptance, the relevant authorities might decide to just consider foundation capacities.

References (2018). International Maritime Organization. [online] Available at: [Accessed 9 Oct. 2018]. (2018). American Bureau of Shipping (ABS) [online] Available at: [Accessed 9 Oct. 2018].

Almeida, R. (2013). Keppel FELS Makes it 66 With Latest Jack-Up Rig Order – gCaptain. [online] gCaptain. Available at: [Accessed 9 Oct. 2018].

DNV GL. (2018). – Safer Smarter Greener – DNV GL. [online] Available at: [Accessed 9 Oct. 2018].

Lloyd’s Register. (2018). Lloyd’s Register offer smart solutions shaped with human intelligence.. [online] Available at: [Accessed 9 Oct. 2018]. (2018). CSME | About. [online] Available at: [Accessed 9 Oct. 2018].

Society of Naval Architects and Marine Engineers. (2018). Home – SNAME. [online] Available at: [Accessed 9 Oct. 2018].

Mitchell, R.F., Miska, S.Z. and Aadnoy, B.S. (2012) Fundamentals of drilling engineering. Richardson, TX: Society of Petroleum Engineers.

Bork, K. (1995). The rotary rig and its components. Austin: Petroleum extension service. Division of continuing education. University of Texas at Austin.

Davis, L. (1995). Rotary, kelly, swivel, tongs, and top drive. 1st ed. Austin: Petroleum extension service. Division of continuing education. University of Texas at Austin.

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