One of the most telling signs of quality design is the careful consideration given to maintenance access for mission-critical equipment within a facility. In the design of bulk fuel storage tanks, the specification of ladders and service platforms can play a crucial role in enhancing the safety and ease-of-maintenance for these systems for years to come. Here’s a comprehensive guide to help you specify these vital components.
Applicable Construction Standards
Ladders and Platforms
- OSHA Standard 1910.28-29: The Occupational Safety and Health Administration (OSHA) sets forth comprehensive standards for the design, construction, and use of fall protection systems, including ladders and platforms. These standards require that:
- Fixed ladders extend at least 42 inches above the landing surface to ensure secure handholds.
- Ladders must be designed to support at least 200 pounds concentrated at any given point.
- Only ladders over 24 feet high should have a personal fall arrest system or a ladder safety system in place to prevent falls. Unless you are working with a vertical fuel tank, this is unlikely to be applicable to your project.
- NFPA 30: The National Fire Protection Association’s standard for flammable and combustible liquids, NFPA 30, addresses safety requirements for storage tanks, including access features like ladders and platforms. It mandates that these components be constructed of non-combustible materials and that they should facilitate safe ingress and egress, especially during emergencies.
- ASTM Standards: Various ASTM standards, including ASTM A123/A123M for zinc (hot-dip galvanized) coatings on iron and steel, are applicable to ensure corrosion resistance, structural integrity, and longevity of ladders and platforms used on fuel storage tanks.
Stairs, Handrails, and Walking Surfaces
- OSHA Standard 1910.23: OSHA’s standard on walking-working surfaces specifies requirements for stairs and handrails. Stairs must have:
- Uniform riser heights and tread depths.
- Handrails installed on both sides if the stairway width exceeds 44 inches. Stairs in fuel tank applications are generally limited to a maximum 36″ width.
- Slip-resistant treads to minimize fall hazards.
- IBC (International Building Code): The IBC regulates stairways and handrails within buildings and industrial structures. In the same manner as OSHA, the IBC also mandates that handrails extend beyond the top and bottom of the stair runs for added safety.
- ANSI/ASSP A1264.1: This standard from the American National Standards Institute and American Society of Safety Professionals provides guidelines on safety requirements for workplace walking and working surfaces, including stairways and handrails. It covers slip resistance, design loads, and edge protection, ensuring that walkways and stairs are safe for workers and compliant with regulations.
Material Considerations
When selecting materials for ladders, platforms, stairs, and handrails, the following considerations are key:
- Corrosion Resistance: Materials like aluminum and galvanized steel are commonly used due to their excellent resistance to rust and corrosion, essential in environments where harsh weather conditions may be present. I recommend against carbon steel painted surfaces on any climbing or walking structures, as the paint will wear off relatively quickly by the foot traffic, and corrosion will develop right away.
- Strength and Durability: All materials must meet the strength requirements specified by OSHA, ASTM, and IBC standards. This ensures that the structures can withstand the expected loads, including the weight of personnel and equipment.
- Non-Slip Surfaces: The walking surfaces, treads, and steps should be designed with non-slip features, such as diamond-plate patterns or applied non-slip coatings, to minimize the risk of falls, especially in wet or oily conditions. Beyond the walking platform, a good option is to also include a non-slip coating on the top surfaces of a cylindrical tank.
Maintenance and Inspection
Regular maintenance and inspections are vital to ensure ongoing compliance and safety. This includes checking for corrosion, verifying that all handrails and ladders are securely attached, and ensuring that walking surfaces remain non-slip. Any damage or wear should be addressed immediately to prevent accidents.
Fall Protection Systems
As mentioned above, for tanks exceeding certain heights, OSHA mandates the installation of fall protection systems. This could include:
- Tie-Off Points: Strategic placement of anchor points for fall arrest systems on and around the tank.
- Guardrails and Self-Closing Gates: Guardrails should be installed around the tank’s perimeter, especially on platforms and walkways, with self-closing gates to prevent accidental falls.
In Practice…
- Reducing “top of tank” procedures such as tank filling, tank gauging, etc, minimizes the exposure of personnel to potentially dangerous situations. Whenever possible, specify ground fill equipment, such as a remote fuel fill port to allow filling of tanks from grade. Large mechanical fuel level gauges, that are visible from the ground, are also a good method to avoid unnecessary climbs to the top of the tank.
- If budget allows, a rectangular tank design provides a flat top surface allowing easier access for inspection and maintenance. However, rectangular tanks can have negative effects on fuel quality. If specifying a rectangular tank with height higher than 4′, you should also specify a handrail system to surround the top surface of the tank.
- There are several design options available for ladders and stairs, to accommodate specific project requirements for space and budget. Regardless of your choice, ensure that the design selection complies with applicable standards, and especially OSHA requirements.
Next Steps…
Specifying ladders, stairs and walking surfaces for bulk fuel storage tanks should be a normal practice for larger tank installations that require “top of tank” access for inspection and maintenance. By following applicable Standards, and by selecting materials that provide both strength and corrosion resistance, you can help safeguard the workers who maintain these critical assets.
For expert assistance in the design and selection of bulk fuel storage tanks and supporting devices, consider partnering with On-Site Power Advisor. With 30+ years of experience in the industry, On-Site Power Advisor offers tailored solutions to meet your project’s needs.