The maximum height an extension ladder can reach is typically around 60 feet. However, the practical working height is usually less due to the overlap required between sections for stability and safety. For instance, a 40-foot extension ladder might have a maximum working height of about 35 feet. The overlap is generally about 3 feet for ladders up to 36 feet and 4 feet for ladders over 36 feet. Additionally, safety guidelines recommend that the ladder should extend at least 3 feet above the roofline or working surface. Therefore, when considering the maximum height an extension ladder can reach, it's important to account for these factors to ensure safe and effective use.

1. **Inspection**: Before use, inspect the ladder for any damage, such as cracks, bends, or missing parts. Ensure all moving parts function properly. 2. **Placement**: Set the ladder on a stable, level surface. Avoid slippery or uneven ground. Use ladder levelers if necessary. 3. **Angle**: Position the ladder at a 75-degree angle. Use the 4-to-1 rule: for every 4 feet of ladder height, place the base 1 foot away from the wall. 4. **Extension**: Extend the ladder to the desired height, ensuring at least three rungs overlap between sections. Lock the rung locks securely. 5. **Top Support**: Ensure the top of the ladder rests against a solid surface. Avoid placing it on unstable or slippery surfaces. 6. **Securing**: If possible, tie the top of the ladder to a secure point to prevent slipping. Use ladder stabilizers for added safety. 7. **Climbing**: Face the ladder while climbing, maintaining three points of contact (two hands and one foot or two feet and one hand). Keep your body centered between the rails. 8. **Tools and Equipment**: Use a tool belt or hoist line to carry tools. Avoid carrying items in your hands while climbing. 9. **Height Limit**: Do not stand on the top three rungs of the ladder. This ensures stability and reduces the risk of falling. 10. **Weather Conditions**: Avoid using the ladder in windy or wet conditions, as this increases the risk of slipping or losing balance. 11. **Electrical Safety**: Keep the ladder away from power lines. Use a non-conductive ladder (fiberglass) if working near electricity. 12. **Supervision**: Have someone hold the base of the ladder if possible, especially if working at significant heights.

The weight capacity of an extension ladder typically falls into one of several duty ratings, which are standardized to ensure safety and reliability. These ratings are determined by the American National Standards Institute (ANSI) and the Occupational Safety and Health Administration (OSHA) in the United States. The main duty ratings for extension ladders are: 1. **Type III (Light Duty)**: Supports up to 200 pounds. Suitable for light household tasks and occasional use. 2. **Type II (Medium Duty)**: Supports up to 225 pounds. Ideal for general household use and some light commercial tasks. 3. **Type I (Heavy Duty)**: Supports up to 250 pounds. Designed for professional use, including construction and industrial applications. 4. **Type IA (Extra Heavy Duty)**: Supports up to 300 pounds. Used for demanding professional tasks and heavy-duty industrial work. 5. **Type IAA (Special Duty)**: Supports up to 375 pounds. Intended for the most rigorous professional and industrial applications. When selecting an extension ladder, it is crucial to consider not only your body weight but also the weight of any tools, equipment, or materials you will be carrying while on the ladder. Exceeding the weight capacity can compromise the ladder's structural integrity, leading to potential accidents or injuries. Always choose a ladder with a duty rating that comfortably exceeds your total weight requirements to ensure safety and stability during use.

1. **Inspection**: Before use, inspect the ladder for any damage or defects. 2. **Positioning**: Place the ladder on a stable, level surface. Ensure the base is one-quarter of the ladder's working length away from the wall (4:1 ratio). 3. **Unlocking**: If the ladder is locked, disengage the rung locks or latches. 4. **Extending**: - Stand the ladder upright. - Grasp the base firmly. - Use a hand-over-hand motion to raise the fly section (the extendable part) by pulling the rope or directly lifting the fly section. - Extend the ladder to the desired height, ensuring it overlaps the base section by at least three rungs. 5. **Locking**: - Engage the rung locks or latches securely onto the rungs of the base section. - Double-check that both locks are fully engaged and the fly section is stable. 6. **Angle Check**: Ensure the ladder is at the correct angle (75 degrees). A quick check is to stand with your toes touching the ladder's feet and extend your arms; your palms should touch the ladder. 7. **Securing**: If possible, secure the top of the ladder to prevent movement. 8. **Climbing**: Face the ladder, maintain three points of contact, and avoid carrying heavy tools while climbing. 9. **Dismantling**: - Descend carefully. - Unlock the rung locks. - Lower the fly section slowly and evenly. - Lock the ladder in its closed position for storage. 10. **Storage**: Store the ladder in a dry, safe place to prevent damage.

Safety standards for extension ladders are primarily governed by OSHA (Occupational Safety and Health Administration) and ANSI (American National Standards Institute) in the United States. Key standards include: 1. **Load Capacity**: Ladders must be rated to support the intended load, including the user and any tools or materials. Common ratings are Type I (250 lbs), Type IA (300 lbs), and Type IAA (375 lbs). 2. **Material and Construction**: Ladders should be made from durable materials like aluminum, fiberglass, or wood, and must be free from defects such as cracks or corrosion. 3. **Design Specifications**: Ladders must have non-slip feet, secure locking mechanisms, and rung spacing of 12 inches. Rungs should be skid-resistant. 4. **Angle and Positioning**: The ladder should be positioned at a 75-degree angle, with the base set one-quarter of the ladder's working length from the wall. 5. **Height and Overlap**: For ladders over 36 feet, a minimum overlap of 3 feet is required between sections. The top of the ladder should extend at least 3 feet above the landing point. 6. **Inspection and Maintenance**: Regular inspections for damage or wear are mandatory. Any ladder found to be defective should be removed from service. 7. **Training and Usage**: Users must be trained in proper ladder use, including maintaining three points of contact, not overreaching, and ensuring the ladder is on stable ground. 8. **Environmental Considerations**: Ladders should not be used in high winds or on slippery surfaces. Fiberglass ladders are recommended for electrical work to prevent conductivity. These standards ensure the safe use of extension ladders, minimizing the risk of accidents and injuries. Compliance with these guidelines is essential for workplace safety.