ASTM D4057 standard practice for manual sampling of petroleum and petroleum products
4. Significance and Use
4.1 Samples of petroleum and petroleum products are obtained for many reasons, including the determination of chemical and physical properties. These properties may be used for: calculating standard volumes; establishing product value; and often safety and regulatory reporting.
4.2 There are inherent limitations when performing any type of sampling, any one of which may affect the representative nature of the sample. As examples, a spot sample provides a sample from only one particular point in the tank, vessel compartment, or pipeline. In the case of running or all-level samples, the sample only represents the column of material from which it was taken.
4.3 Based on the product, and testing to be performed, this practice provides guidance on sampling equipment, container preparation, and manual sampling procedures for petroleum and petroleum products of a liquid, semi-liquid, or solid state, from the storage tanks, flowlines, pipelines, marine vessels, process vessels, drums, cans, tubes, bags, kettles, and open discharge streams into the primary sample container.
5. Health and Safety Precautions
5.1 General - This practice does not purport to cover all safety and health aspects associated with sampling. Personnel involved with sampling of petroleum and petroleum-related products should be familiar with their physical and chemical characteristics, including: potential for fire, explosion, and reactivity; toxicity and health hazards; and appropriate emergency procedures. Additionally personnel should comply with individual company safe operating practices and local, state, and national regulations, including the use of personal protective equipment (PPE). Upon completion of any sampling activity, ensure the sample point is left in a safe, secure, and clean condition with the handling of any waste in accordance with local requirements. All marine vessel sampling should be performed in the presence of a designated vessel representative.
5.2 Sample Handling - For safety and protection of the integrity of the samples, sample carriers are suggested in most instances. Refer to Fig. 6. Because of potential liquid thermal expansion, sample containers that are completely, or nearly full, are not to be transported or stored, unless special precautionary measures are taken. A safe fill of between 70 and 85 % is recommended. Refer to definition for maximum fill density and 9.30 for safe fill of pressurized cylinders. Take care to avoid heating samples in containers with gas-tight caps, lids, and stoppers. Handle any sample containing hazardous materials or the residue of hazardous materials offered for shipment/transportation by air, public roadway, rail, or water in such a manner as to ensure compliance with requirements such as training, documentation, labeling, container, packaging, communications, and so forth, set forth in applicable regulations, such as those issued by the International Air Transport Association (IATA) and the U.S. Department of Transportation (DOT).
5.3 Sample Point Safety:
5.3.1 Provide sample points that enable samples to be taken in a safe manner, considering ventilation during sampling, clear access/egress, and lighting. Any potential hazards associated with sampling, or located near the sample point, should be clearly marked. It is recommended that a pressure gauge and a method of closed loop flushing with safe drainage, be provided at pipeline sample points. Sample points and related equipment should be maintained and inspected regularly.
5.3.2 Floating-roof tanks should be sampled from the top platform, thereby avoiding descent onto the floating roof. Descending onto a floating roof is normally considered entering a designated confined space, requiring all facility and regulatory requirements to be strictly followed, including obtaining a confined space permit, and rescue provisions arranged. Toxic and flammable vapors may accumulate on the roof.
5.4 Static Electricity Hazards:
5.4.1 A number of fires and explosions have occurred as a result of hydrocarbon vapors being ignited by static electricity. If electrical charges are not earthed or grounded, they are unable to dissipate and become "static". This static electric charge can accumulate and freely migrate to a single point on the sample container by a difference in electrical potential, then jump off as a high-energy spark discharge to a nearby less charged surface, often hot and prolonged enough to ignite nearby hydrocarbon vapors above the lower explosive limit (LEL). This potential shall be managed by safely dissipating static charges, and through proper grounding, when sampling flammable products.
5.4.2 Footwear or clothing, capable of causing sparks, should not to be worn during sampling activities in which flammable vapors are likely to be present. Sampling should not be carried out during periods of atmospheric electric disturbance or hail storms. To ground any static charge on their person, the individual performing the sampling should touch part of the tank structure at least 1 m (3 ft) from the sample point immediately before sampling.
5.4.3 Precautions are to be observed before sampling to reduce the likelihood of a static charge being present. During tank filling or mixing operations, and for 30 min after the completion, sampling equipment shall not be introduced into, or remain in, the tank. With full observance of applicable regulatory requirements, and only under very specific and documented conditions, some exceptions to the 30-min relaxation period may apply. Some tanks and vessel compartments have inert gas blankets in the vapor space above the liquid. Unless the effectiveness of the inert blanket can be verified, all static charge precautions and recommendations should be observed.
5.4.4 Exercise caution when using equipment made of aluminum, magnesium, or titanium, which may generate incendiary sparks when struck against rusted steel. Some countries restrict the use of sampling equipment made from such materials or from alloys containing more than 15 % (m/m) in total of these metals or 6 % (m/m) of magnesium.
5.5 Pipeline/Line Sampling - When sampling from a flowing pipeline, maintain electrical continuity between the pipeline and the sample container via the connecting pipework. Do not use plastic containers since they are non-conductive and will not dissipate static electricity. Use a static grounding clamp or other arrangement that ensures adequate electrical continuity is maintained if sampling with a metal container. An effective ground should be verified.
NOTE 1 - The API safety publication Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents states that electrical resistances of higher than 10 in metal circuits are indicative of a break in the continuity of the circuit, resulting in the undesirable accumulation of static electricity.
5.6 General Health Hazards and Precautions:
5.6.1 Petroleum vapor dilutes oxygen in the air and may also be toxic. Hydrogen sulfide vapors are particularly hazardous. Harmful vapors or oxygen deficiency cannot always be detected by smell, visual inspection, or judgment. The use of oxygen and toxic gas monitors, PPE, and emergency rescue precautions should be considered for all sampling operations. Self-contained breathing apparatus (SCBA) may be necessary. Personnel should position themselves upwind of the sample point to minimize exposure to any harmful vapor which may be released.
5.6.2 This discussion on safety and health is not exhaustive. The appropriate Material Safety Data Sheet (MSDS), API, or ASTM International publication should be consulted, together with applicable regulatory requirements, and the International Safety Guide for Oil Tankers and Terminals (ISGOTT), Safety of Life at Sea (SOLAS), and Oil Companies International Marine Forum (OCIMF), while always observing company and local health and safety requirements.
