Manufacturer briefing: Equipment for explosive atmospheres

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In the marine and oil & gas industries, a whole raft of equipment is used for applications such as pipe cleaning, surface preparation, fluid transfer, painting and lubrication. Equipment supporting these applications can be found on oil tankers, cargo ships, crude carriers, LNG/LPG tankers, oil refineries, drilling platforms and floating storage units. All of these application areas have a common denominator: their atmospheres are potentially explosive. This means that any equipment used there must be ATEX approved.
ATEX is an abbreviation for the ATEX Directive and is also short for “Atmospheres Explosibles”. The ATEX Directive is a set of European Union regulations designed to ensure the safety of products being used in a potentially explosive atmosphere. An explosive atmosphere is defined as a mixture of flammable substances (gases, vapors, mists or dusts) with air, under atmospheric conditions capable of causing a hazardous explosion if ignited.
ATEX Directive 2014/34/EU from the European Commission requires equipment and protective systems intended for explosive atmospheres to be designed and manufactured to minimize the occurrence and limit the severity of accidental explosions. It applies to:
• New equipment intended for use in explosive atmospheres, such as electrical components and machinery.
• Separately supplied protective systems for controlling unavoidable explosions in explosive atmospheres such as explosion vents, suppression systems, etc.
A similar certification is IECEx, which stands for International Electrotechnical Commission Explosive. There are some small differences between the two certifications. For example, IECEx does not evaluate non-electrical equipment for use in hazardous locations; non-electrical is only recognized under the ATEX Directive. Another difference is the geographical location where the certification is recognized and accepted. While ATEX is a requirement in Europe, IECEx is accepted in many countries internationally.
Flammable substances and ATEX Zones
A flammable substance includes any substance or preparation which, because of its properties or the way it is used, can cause harm to people from fires and explosions. Examples are diesel, petrol, LPG, chemicals, paints, varnishes and solvents. ATEX regulations apply to most workplaces where flammable substances are stored or used. Typical examples are vessels or plants where flammable liquids are present or where flammable dusts are produced in the process.
If an explosive atmosphere of flammable substances is specified, zones may exist for gases/vapor or for dust:
• Zone 0 (gases/vapors) or Zone 20 (dusts): An area in which an explosive mixture is continuously present or present for long periods.
• Zone 1 (gases/vapors) or Zone 21 (dusts): An area in which an explosive mixture is likely to occur in normal operation.
• Zone 2 (gases/vapors) or Zone 22 (dusts): an area in which an explosive mixture is not likely to occur in normal operation and if it occurs it will exist only for a short time.
The illustration shows an example of the differences between zones.

Certain equipment may be approved for use in Zone 1 and Zone 2 area classifications only. This means it is not approved for use in a Zone 0 location. In other words, it’s approved to operate in an explosive atmosphere consisting of a mixture of flammable substances that can form occasionally in normal operation.
What do the ATEX markings mean?

Here’s an example of an ATEX marking on a Graco product (EcoQuip):

And this is the explanation of each marking:

The product complies with the ATEX Directive

 

Specific marking for explosion protection
II Equipment Group (Surface Industry)
2 Equipment Category (use in Zone 1 or Zone 2)
G Environment (Gases)
c Type of Protection (Constructional Safety, Mechanical)
ia Intrinsically Safe (DataTrak)
llA Gas Group (Propane)
T3 Temperature Class (T1 – T6: T3 = 200°C)
X Special conditions for safe use. Listed in the warning section of the operations manual

What Graco equipment is ATEX certified?
Some Graco products that are commonly used in the marine and oil & gas industries and which are ATEX certified are EcoQuip Vapor Abrasive Blast Equipment, King Airless Industrial Coatings Sprayers, and the e-Xtreme Electric Airless Sprayer. The entirety of each of these products has ATEX approval; not just individual components. Moreover, they are all classified as both ATEX and IECEx certified.
Of these three products, one of the most frequently used in these industries is EcoQuip. Here is an overview of an in-depth independent test that was carried out to approve EcoQuip for use in potentially explosive atmospheres caused by gases and vapors. It’s followed by a real-life case study in an oil & gas refinery in the United Arab Emirates.
1) EcoQuip confirmed as suitable for explosive atmospheres
EcoQuip is Graco’s vapor abrasive blasting equipment. It’s been proven to be suitable in different industries for a range of applications such as the removal of paint, rust, corrosion, industrial coatings and linings; for cleaning metal, stone and woodwork; and for building and site maintenance. In all these applications, EcoQuip has been demonstrated to reduce project costs and increase the speed, efficiency and productivity of blasting.
In the marine and oil & gas industries, abrasive blasting often has to take place in a potentially explosive atmosphere. In such an environment, it’s vital to use abrasive blasting equipment that has been fully tested to determine whether the blasting process might lead to an ignition.
Gexcon AS of Bergen, Norway, a world-leading company in the field of safety and risk management and advanced dispersion, explosion and fire modelling, was asked to perform tests to determine whether sparks generated by the EcoQuip system would be potential sources of ignition. The experiments were performed at Gexcon’s test site at Børnesskogen, Norway in May 2019.
EcoQuip is intended – and is ATEX approved – for use in atmospheres of flammable materials in the Equipment Protection Level (EPL) Subgroup IIA. This subgroup of explosive gases includes diesel fuels, petrol fuels, hexane, methanol, propane, ethane, acetone, toluene, benzene and methane.
For the purposes of this test, hexane was selected. At a concentration of only around 4% in air, hexane is not only extremely sensitive to electrical sparks, but is easy to ignite with a spark. It has an auto ignition temperature of 230 °C. Tests were therefore performed in explosive atmospheres with a rich concentration of n-hexane.
The tests were performed in a 50 cubic meter testing vessel. It had to be relatively large due to the air coming into the system from the blasting equipment diluting the gas mixture. Its large size would also permit a longer duration of the tests. The vessel was open at one end, which was covered with a plastic sheet to contain the combustible gas/air inside the vessel as well as to relieve the pressure of an explosion should one occur.
The vessel was equipped with a recirculation system with a n-hexane evaporation system. Pure n-hexane vapor was injected into the recirculation system to gradually increase the n-hexane concentration inside the vessel. N-hexane concentrations around 7% were normally used as the starting concentration and diluted to around 4% for all tests. The mixture of n-hexane vapor and air inside the vessel was monitored with a binary gas analyzer from Stanford Research Systems Inc.
EcoQuip was positioned on the outside of the test vessel, while the nozzle was inside the test vessel. A Graco standard #7 blast nozzle (7/16″, 11 mm) was used during the tests. The nozzle was connected via a 15 meter hose to the equipment. EcoQuip was earthed to the test vessel using its green earthing cable. The nozzle was mounted in rubber mounting brackets to prevent it from being earthed to the steel in the vessel in order to best simulate a person holding the nozzle. EcoQuip was supplied with water from a 1000 liter water tank standing on the roof of the testing vessel, about 3 meters off the ground. Only gravity from this tank was used to supply the system with water. A Kaeser M122 air compressor provided a steady pressure of typically 7.5 bar (110 psi).
Five different abrasives were used with the Graco EcoQuip vapor abrasive blasting equipment during the test:
• 30/60 mesh Garnet (GMA)
• 80 mesh Garnet (GMA)
• Fine Copper Slag 0.2-1.0 mm grit size (Star Grit)
• Coarse Copper Slag 0.4-1.9 mm grit size (Star Grit)
• Fine Crushed Glass 0.2-0.6 mm.
Blasting was performed on rusty steel and aluminum plates of approximately one square meter. These could be moved during a test, making it possible to blast on new material. The five abrasives were used on both steel and aluminum plates, making a total of ten test runs. The duration of each test run lasted between 3.2 and 7.5 minutes. The abrasives and blasting materials were chosen to cover the typical worst-case combinations when it comes to spark generation.
None of the tests yielded an ignition. After the last test, the explosive atmosphere inside the vessel was ignited using an oscillating spark in order to confirm that the atmosphere was indeed explosive. (It was!).
Gexcon therefore fully endorses Graco’s EcoQuip vapor abrasive blasting equipment as suitable for use in potentially hazardous areas involving explosive atmospheres caused by gases and vapors of the Subgroup IIA. These tests support EcoQuip’s ATEX ignition hazard analysis for category 2 equipment, zone 1 explosive atmospheres.
2) ADNOC approves EcoQuip
Das Island is a small, almost rectangular island in the Persian Gulf, located about 100 miles (160 km) north-west of the mainland of the United Arab Emirates. Oil production here began after prospecting during 1956-1960 by Abu Dhabi Marine Areas (ADMA), a joint venture between British Petroleum and Compagnie Française des Pétroles (later known as Total). Since then the island has become a major center for the oil & gas industry in the region, exporting crude oil and liquefied natural gas by tankers as far as Japan and Europe.

Another company with a major presence on Das Island is the Abu Dhabi National Oil Company (ADNOC). ADNOC’s commitment to environmental protection, continually assessing and actively managing environmental risks and impacts falls in line with the UAE’s commitment to achieving its ecological responsibility. Great emphasis is placed on the identification and mitigation of Health, Safety and Environmental (HSE) risks. Like ADNOC’s various business units, its LNG unit and Corrosion & Detection Department (C&ID) operating on Das Island are required to pass a stringent Health, Safety and Environmental Impact Assessment (HSEIA).
Corrosion Under Insulation (CUI) is a particularly prevalent problem for the oil & gas industry in hot and humid marine environments. It refers to the type of corrosion that occurs due to a moisture build-up on the external surface of insulated equipment. This can be caused by a number of factors, but commonly leads to galvanic, chloride, acidic or alkaline corrosion. If undetected, the results of CUI can lead to the shutdown of a process unit or an entire facility, and in rare cases it may lead to a process safety incident.
The management of CUI on a live working oil & gas refinery is therefore a constant challenge for ADNOC’s asset maintenance teams. Keeping CUI under control requires the removal of previous coatings. Traditionally this is carried out utilizing conventional Dry Abrasive Blasting systems. However, the environmental impact that these systems are having on the marine life around the Das Island refinery has become a cause for concern.
ADNOC’s Corporate Paint and Insulation Inspector, Lee Wilson, renowned author of The Paint Inspectors Guide, therefore had a challenge on his hands. Not only was he looking to evaluate alternative surface preparation methods to Dry Abrasive Blasting, but he wanted to reduce waste management and adopt a surface preparation system that maintains ADNOC’s Standard Operating Procedures and environmental compliance as stipulated by the HSEIA.
Wilson’s evaluation process led him to shortlist Graco’s EcoQuip Vapor Abrasive Blasting equipment as a possible solution for ADNOC. The Graco team were delighted at the opportunity to work with an industry leader and influencer like Lee Wilson, who took time out of his busy schedule to travel to Graco’s European headquarters in Maasmechelen, Belgium. Various live demonstrations and tests were carried out to assess EcoQuip’s capabilities as an alternative surface preparation method.
Wilson concluded that EcoQuip demonstrated its capabilities as the ideal solution for the projects he manages for ADNOC on Das Island. “I found Vapor Abrasive Blasting exceptional as a means to remove Corrosion Under Insulation It’s the ideal solution to blast sweating and iced lines while maintaining our standard operating procedures with regards to minimum and maximum cleaning requirements,” he said.
Additionally, he was impressed at the multiple benefits offered by EcoQuip VAB compared to Dry Abrasive Blasting. “Vapor Abrasive Blasting will dramatically improve ADNOC’s waste management and abrasive containment issues across Das Island. Moreover, EcoQuip’s ability to remove soluble salts is an additional performance benefit, as it increases the longevity of coatings.”
Consequently, Graco is proud to announce that the Abu Dhabi National Oil Company LNG C&ID has approved Graco’s EcoQuip Vapor Abrasive Blasting unit for on-site implementation directly and by approved contractors.

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