For decades, open sampling was the standard method used across the petroleum and chemical inspection industries. Inspectors routinely climbed tanks, opened hatches, and lowered samplers directly into the product. Although this approach provided direct access, it also exposed inspectors to vapors, unexpected pressure releases, and potentially volatile atmospheres—especially in chemical reactors and heated storage systems. Over the years, as regulations evolved and safety expectations increased, the industry began shifting away from open methods. Today, closed-loop sampling has become the preferred—and increasingly required—standard across the Testing, Inspection & Certification (TIC) sector.
Closed systems represent one of the most significant advancements in field safety. Instead of exposing the product to the atmosphere, inspectors connect specialized equipment to a dedicated valve or sampling port, allowing material to flow directly into a gas-tight container. By eliminating open hatches and minimizing exposure, closed sampling dramatically reduces the risk posed by vapor release, elevated work, and reactive or oxygen-sensitive products. What may seem like a procedural update is, in practice, a transformational improvement in operational safety.
Regulatory pressure has played a substantial role in accelerating this transition. OSHA in the United States emphasizes limiting exposure to flammable vapors and confined-space hazards. Similarly, European directives, including ATEX and worker protection regulations, push operators toward engineering controls that reduce volatile emissions and prevent atmospheric contamination. International guidance from API and ASTM continues to reinforce the benefits of closed systems, and many refineries, terminals, and pipeline companies have begun adopting policies that allow sampling and gauging only through closed methods. The result is an industry-wide movement toward safer, controlled, and compliant sampling operations.
Closed systems also support growing environmental expectations. Traditional open sampling can release hydrocarbons into the air, contributing to fugitive emissions. As global environmental standards tighten—whether through the EU Industrial Emissions Directive, EPA air-quality rules, or local VOC regulations—operators face increased scrutiny regarding how tanks are accessed and handled. Closed sampling drastically reduces unnecessary vapor release, demonstrating a facility’s commitment not only to regulatory compliance but also to broader sustainability goals.
An additional benefit of closed-loop systems is improved sample integrity. Open sampling can introduce contaminants such as airborne particles, moisture, or oxygen, all of which may alter the composition of sensitive materials. Products such as FAME biodiesel, HVO blends, pyrolysis oils, waste-derived feedstocks, and certain petrochemicals are especially susceptible to oxidation or environmental contamination. Closed systems limit exposure and preserve the chemical characteristics of these fuels and intermediates, allowing laboratories to produce more accurate and reliable analytical results.
As the energy transition accelerates and renewable fuels enter mainstream markets, the relevance of closed sampling becomes even more pronounced. Novel intermediates, waste-derived oils, and SAF blending components often contain reactive compounds and strong vapors that degrade quickly when exposed to air. Ensuring these samples are collected in a closed, controlled manner is essential for meaningful laboratory analysis and for meeting the requirements of emerging standards such as ASTM D7566 and various low-carbon fuel frameworks.
Closed systems also bring greater operational efficiency. Inspectors can often complete sampling more quickly because tanks may not require depressurization or extended ventilation. Facilities with standardized sampling valves reduce delays during high-traffic activities such as vessel loading, pipeline transfers, and turnaround events. The more consistent the sampling infrastructure becomes, the smoother coordination is between operators and inspectors, improving throughput without compromising safety.
This industry evolution also creates a growing need for training and cross-functional cooperation. Inspectors must be familiar with different closed-loop system designs, valve types, purging procedures, and leak-tight verification. Facilities, in turn, must ensure that sampling ports are properly maintained, labeled, and compatible with inspection equipment. The transition to closed systems requires shared responsibility among TIC providers, operators, and facility personnel—strengthening communication and reinforcing a culture of safety.
Ultimately, the move toward closed sampling reflects not just a technical improvement but a cultural shift. Clients increasingly expect their TIC partners to demonstrate adherence to modern safety and environmental practices. Companies that continue relying on outdated open sampling methods risk regulatory penalties, operational disruption, and diminished client confidence. Those that embrace closed systems position themselves as forward-thinking, compliant, and aligned with the expectations of a rapidly evolving industry.
AmSpec has been proactive in adopting these new standards. Across our operations, we are implementing closed-system sampling procedures supported by investments in equipment, training, and alignment with global regulations such as ASTM, ISO, API, OSHA, and European safety directives. Combined with our ISO 17025-accredited laboratories and experienced global inspection workforce, AmSpec continues to provide safer, more reliable sampling solutions that protect people, preserve sample integrity, and help clients meet the increasing demands of environmental and regulatory compliance.
Closed systems are reshaping how the industry works. AmSpec is committed to leading that transformation.