This document describes the 3M DBI-SALA Sealed-Blok Self-Retracting Device (SRD), a component of a personal fall protection system designed for worker mobility and fall protection. The SRD is suitable for applications where the lifeline remains generally vertical and free fall is limited to 2 ft (0.6 m).
Function Description:
The Sealed-Blok SRD is a drum-wound wire rope lifeline (A) that retracts into a sealed aluminum housing (B). It is designed to arrest a fall by activating a speed-sensing brake system. The device can be attached to an anchorage point via a carabiner through a swivel eye (C) on top of the SRD. A self-locking snap hook (D) at the end of the lifeline connects to the designated fall arrest connection on a full body harness. A bumper (E) protects the wire rope and ferrules from abrasion and corrosion.
Some models, designated as SRL-R and SRL-RSQ, include integral means for assisted rescue. SRL-Rs are equipped with a 3-Way Emergency Retrieval Hand Crank (Figure 2B), allowing for raising or lowering the rescue subject. SRL-RSQs feature an RSQ Rescue/Descent Knob (Figure 2C) for automatic or assisted descent. Some rescue models may include both components (Figure 2D) and a Tripod Mounting Bracket (I) for confined space applications.
Important Technical Specifications:
- Capacity: For one person with a combined weight (clothing, tools, etc.) from 130 lbs (59 kg) to 310 lbs (141 kg) per ANSI Z359.14 Class B requirements. Some SRDs also support a 420 lbs (191 kg) maximum capacity per OSHA.
- Lifeline Lengths: Available in 50 ft (15 m), 85 ft (26 m), 130 ft (40 m), and 175 ft (53 m) options.
- Lifeline Material: 3/16 inch (4.76 mm) galvanized wire rope or stainless wire rope.
- Casing: Sealed aluminum casing.
- Snap Hook: Swiveling self-locking snap hook with impact indicator, available in plated steel (2000180) or stainless steel (2000181).
- Gate Strength: 3,600 lbs (16 kN).
- Throat Size: 3/4 inch (1.9 cm).
- Maximum Arrest Force: 1,350 lbs (6 kN).
- Average Arrest Force: 900 lbs (4 kN).
- Maximum Arrest Distance: 42 inches (1.1 m).
- Average Locking Speed: 4.5 ft/s (1.4 m/s).
- RSQ Descent Speed Range: 2-3 ft/s (0.6 - 0.9 m/s).
- Lifeline Tensile Strength: Galvanized Steel - Min. 4,200 lbs (18.7 kN); Stainless Steel - Min. 3,600 lbs (16.0 kN).
Usage Features:
- Normal Operation: The lifeline extends and retracts without hesitation or slack during normal worker movement. Sudden or quick movements should be avoided as they may cause the SRD to lock up.
- Body Support: A full body harness must be used. The harness connection point should be above the user's center of gravity. Body belts are not authorized for fall arrest applications.
- Anchorage: Anchorages must be capable of sustaining static loads of at least 5,000 lbf (22.2 kN) for non-certified anchorages, or two times the maximum arresting force for certified anchorages. The anchorage point should be directly overhead to minimize swing falls.
- RSQ™ Dual-Mode (SRL-RSQ models): Allows selection between "Fall Arrest" and "Descent" modes using the RSQ Engagement Knob. In "Descent" mode, the user automatically descends after a fall. In "Fall Arrest" mode, the SRD arrests the fall, and the user remains suspended. Descent can be activated and controlled using the Engagement Knob Pull Ring or an optional Extension Pole Release Tool.
- Retrieval Operation (SRL-R models): The integral rescue hand crank allows for raising or lowering the lifeline for rescue purposes. It is not intended for work positioning or material lifting/lowering. A minimum load of 75 lbs (33.9 kg) is required to lower or pay out the lifeline.
Maintenance Features:
- Inspection Frequency: SRDs must be inspected by an authorized person or rescuer before each use. A competent person must conduct additional inspections annually, or more frequently under harsh working conditions.
- Inspection Criteria: Inspections include checking for loose/damaged parts, housing distortion, cracks, swivel eye integrity, proper lifeline retraction and locking, and legibility of labels. The swivel snap hook and impact indicator must also be inspected. If the impact indicator shows a red band, the SRD must be removed from service.
- Lifeline Inspection: The wire rope lifeline should be checked for cuts, kinks, broken wires, bird-caging, welding splatter, corrosion, chemical contact, or abraded areas. If six or more randomly distributed broken wires in one lay, or three or more broken wires in one strand in one lay are found, the lifeline assembly must be replaced.
- Reserve Lifeline Inspection: If the button stop (A) on the reserve lifeline is visible, the reserve lifeline is spent and must be replaced.
- Cleaning: Periodically clean the exterior of the SRD and the lifeline with water and a mild soap solution. Do not force dry with heat.
- Service: FAST-Line Lifelines can be replaced in the field by a competent person using the FAST-Line Lifeline Replacement Kit. All other service must be performed by an authorized service center. Do not attempt to disassemble or lubricate any parts.
- RFID Tag: Some SRDs include an RFID tag for simplified inspection and inventory control, allowing data transfer to a web-based log.
- Product Life: The functional life is determined by work conditions and maintenance. The product remains in service as long as it passes inspection criteria.
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