512 EM 385-1-1 Chapters 16-22

Sections

21-8. General Requirements.

Safety Net Systems (Passive Fall Protection Systems)

Install safety nets under work surfaces as close as close under the work surfaces as practical, but in no case more than 30 feet below the work surface. Hang nets with sufficient clearance to prevent contact with the surfaces or structures below. Determine the clearance by impact load testing.
Ensure the mesh size does not exceed specified dimensions and the border rope has a minimum breaking strength.
Only use safety nets after they have been tested or certified by a Qualified Person (QP), with all tests supervised and results maintained.

Other Engineered Fall Protection Systems

A QP must design, install, certify, and oversee the use of engineered fall protection systems, adhering to manufacturer instructions.
The design must include detailed instructions and clearances, with systems approved by the USACE supervisor, KO, or COR.

Warning Line System (WLS) (Administrative Control)

Erect warning lines around work areas on roofs, maintaining specified distances from edges and ensuring high visibility and strength.
Connect access, material handling, storage, and hoisting areas to work areas using warning lines, and use additional fall protection systems outside the WLS.
For non-roofing activities on low-sloped roofs, contractors must ensure the warning line meets specific requirements and no work is performed between the warning line and the edge or hole.

Designated Areas (Administrative Control)

Ensure employees stay within the designated area with boundaries clearly visible and strong enough to withstand specified forces.
Position the designated area appropriately from the edge, adjusting based on the type of work and use of mobile mechanical equipment.

Safety Monitoring System (SMS) (Administrative Control)

Use an SMS in conjunction with another fall protection control and ensure it is not used independently as a fall protection method.

Knowledge Check Choose the best answer for the question.

21-8. Safety nets should not be installed more than _____.

15 feet or more below the work surface

10 feet above the lower work surface

30 feet below the work surface

20 feet under the work surface

You forgot to answer the question!

EM 385-1-1 Paragraph 21-8 (g.–k.).

21-8. General Requirements. (g.–k.).

g.  Safety Net Systems (Passive Fall Protection Systems).  Design, install, use, and maintain safety net systems for fall protection according to ANSI/ASSP A10.11 and 29 CFR 1926.502 (29 CFR 1926 Subpart M).  (21-8.g)

Note. See chapter 14 for debris nets.

(1)  Install safety nets as close under the work surfaces as practical, but in no case more than 30 feet (9.1 m) below the work surface.  Hang nets with sufficient clearance to prevent contact with the surfaces or structures below.  Determine the clearance by impact load testing.

(2)  When nets are used on bridges, multi-story buildings or structures, ensure that the potential fall area from the walking or working surface to the net is unobstructed.

(3)  The maximum size of the mesh openings must not exceed 36 in2 (232.3 cm2), nor be longer than 6 inches (15.2 cm) on any side.

(4)  The border rope or webbing must have a minimum breaking strength of
    5,000 pounds (22.2 kN).

(5)  Do not perform work requiring safety net protection until the nets are in place and have either been tested without failure according to the following procedures, or a QP states otherwise.

(a)  Test safety nets and safety net installations while in the suspended position immediately after installation.  Perform the tests under the supervision of QP and in the presence of the USACE supervisor/KO or COR.  Test whenever nets are relocated, after any major repair, and at least every six months if left in place for extended periods.

(b)  Perform a drop test.  Use a 400 lb. (181.4 kg) bag of sand that is not more than 30 inches +/- 2 inches (76.2 cm +/- 5.1 cm) in diameter.  Drop the bag from at least 42 inches (106.7 cm) above the highest working or walking surface at which workers are exposed to fall hazards.  Ensure the weight can be safely retrieved after the test is conducted.

(c)  The drop test is not necessary if a QP certifies in writing that it is unreasonable to perform the drop test.  The certification must state that the net and its installation, to include anchorages, are in compliance with manufacture’s recommendations, this manual, applicable federal, state, and local requirements.  The QP must sign the certification and include an identification of the net and net installation, and the certification date.  Maintain a copy of the certification at the jobsite.

(6)  Use only shackles and hooks made of forged steel.

(7)  When debris nets are used with safety nets, secure them on top of the safety net.  Ensure that they do not compromise the design, construction, or performance of the safety nets.

(8)  Remove any materials, scrap pieces, equipment, and tools that have fallen into the safety net as soon as possible and at least before the next work shift.  Protect safety nets from sparks and hot slag resulting from welding and cutting operations.

(9)  If any welding or cutting operations occur above the nets, provide noncombustible barriers.  Increase the frequency of inspections in proportion to the potential for damage to the nets.   (See para 21-5.b)

h. Other Engineered Fall Protection Systems.  Commercially available engineered and integrated systems are recognized as effective fall protection and may be used provided the requirements of paragraph 21-8.h are met.  (21-8.h)

(1)  A QP must design, install, certify, and supervise the use of all commercially available engineered and integrated systems.  They must be used according to the manufacturer’s instructions and recommendations.  The CP may, if deemed appropriate by and under the direction of a QP, supervise the assembly, disassembly, use, and inspection of the engineered system.

(2)  The design must include drawings, required clearances, and instructions on proper installation, use, and inspection requirements.  The USACE supervisor must approve or the KO or COR must accept these systems as part of the Fall Protection and Prevention Plan.

i. Warning Line System (WLS) (Administrative Control).  (21-8.i)

(1)  Construction Roofing Activities on Low-Sloped Roofs.  Employees engaged in construction roofing activities on low-sloped roofs (that is, 18.4, 4:12) with unprotected sides and edges 6 feet (1.8 m) or more above lower levels can utilize a WLS. At minimum, the WLS must be used in combination with a safety monitor system (see 29 CFR 1926.501(b)(10) and 1926.502(h) (29 CFR 1926 Subpart M)).  WLS must comply with the following:

(a)  The warning line must be erected around all sides of the roof work area.

(b)  When mechanical equipment is not being used, the warning line must be erected not less than 6 feet (1.8 m) from the roof edge.

(c)  When mechanical equipment (as defined by 29 CFR 1926.500(b) (29 CFR 1926 Subpart M)) is being used, the warning line must be erected not less than 6 feet (1.8 m) from the roof edge which is parallel to the direction of mechanical equipment operation, and not less than 10 feet (3 m) from the roof edge which is perpendicular to the direction of mechanical equipment operation.

(d)  Points of access, materials handling areas, storage areas, and hoisting areas must be connected to the work area by an access path formed by two warning lines.

(e)  When the path to a point of access is not in use, a rope, wire, chain, or other barricade, equivalent in strength and height to the warning line, must be placed across the path at the point where the path intersects the warning line erected around the work area, or the path must be offset such that a person cannot walk directly into the work area.

(f)  Warning lines must consist of ropes, wires, or chains, and supporting stanchions erected as follows:

(f-1)  The rope, wire, or chain must be flagged at not more than 6 feet (1.8 m) intervals with high-visibility material.

(f-2)  The rope, wire, or chain must be rigged and supported in such a way that its lowest point (including sag) is no less than 34 inches (86.4 m) from the walking/working surface and its highest point is no more than 39 inches (99.1 cm) from the walking/working surface.

(f-3)  After being erected, with the rope, wire, or chain attached, stanchions must be capable of resisting, without tipping over, a force of at least 16 pounds (0.07 kN) applied horizontally against the stanchion, 30 inches (76.2 cm) above the walking/working surface, perpendicular to the warning line, and in the direction of the floor, roof, or platform edge.

(f-4)  The rope, wire, or chain must have a minimum tensile strength of 500 pounds (2.22 kN), and after being attached to the stanchions, must be capable of supporting, without breaking, the loads applied to the stanchions as prescribed above.

(f-5)  The line must be attached at each stanchion in such a way that pulling on one section of the line between stanchions will not result in slack being taken up in adjacent sections before the stanchion tips over.

(g)  An additional fall protection system is required when working outside the WLS.

(h)  Mechanical equipment on roofs must be used or stored only in areas where employees are protected by a WLS, guardrail system, or PFAS.

(2)  Construction Activities on Low-Sloped Roofs Regardless of Trade.  Applies to contractors only. USACE employees are not permitted to use WLS in this manner.

(a)  Contractor employees engaged in construction, non-roofing activities on low- sloped roofs (that is, less than 18.4, 4:12) with unprotected sides or edges 6 feet (1.8 m) or more above lower levels can utilize a WLS.  The WLS must comply with the following:

(a-1)  The warning line is erected at least 15 feet from the edge or nearest edge of a hole.

(a-2)  The warning line meets or exceeds the requirements of paragraph 21-8.i and 29 CFR 1926.502(f)(2) (29 CFR 1926 Subpart M).

(a-3)  No work or work-related activity is performed in the area between the warning line and the hole or edge.

(a-4)  The employer effectively implements a work rule prohibiting employees from going past the warning line.

Note. Paragraph 21-8.i(2) is not in compliance with current OSHA standards, however, OSHA has issued response that a warning line erected at least 15 feet from an edge or hole combined with effective work rules can be expected to prevent employees from going past the line and approaching the fall hazard.  In addition, at a distance of 15 feet, the absence of a barrier to restrain employees from unintentionally crossing the line would not place the employee in immediate risk of the fall hazard. Therefore, OSHA will apply a de minimis policy for non-conforming guardrails for WLS used in this manner.

(b)  Contractors must determine if paragraph 21-8.i(2)(a) is acceptable to complete their work activities. Procedures and work practices must be documented in their Fall Protection and Prevention Plan (see para 21-7).

j. Designated Areas (Administrative Control).  A designated area is a distinct portion of a walking-working surface delineated by rope, wire, tape, or chain in which employees may perform work without additional fall protection during general industry type work (for example, inspecting or maintaining HVAC equipment).  Working within a designated area does not require additional fall protection, however, if working outside the designated area, another form of fall protection must be provided when personnel are exposed to fall hazards (see figure 21-2).  When the employer uses a designated area, the employer must ensure the following:  (21-8.j)

(1)  Employees remain within the designated area while work operations are underway.

(2)  The perimeter of the designated area is delineated with rope, wire, tape, or chain that has a minimum breaking strength of 200 pounds (0.89 kN) and is installed so its lowest point, including sag, is not less than 34 inches (86.4 cm) and not more than 39 inches (99.1 cm) above the walking-working surface.

(3)  Is supported in such a manner that pulling on one section of the line will not result in slack being taken up in adjacent sections causing the line to fall below the limits specified above.

(4)  Is clearly visible from a distance of 25 feet (7.6 m) away, and anywhere within the designated area.

(5)  Is erected as close to the work area as the task permits.

(6)  Is erected not less than 6 feet (1.8 m) from the roof edge for work that is both temporary and infrequent, or not less than 15 feet (4.6 m) for other work.

(7)  When mobile mechanical equipment is used to perform work that is both temporary and infrequent in a designated area, the employer must ensure the rope,
    wire, tape, or chain is erected not less than 6 feet (1.8 m) from the unprotected side or edge that is parallel to the direction in which the mechanical equipment is operated, and not less than 10 feet (3 m) from the unprotected side or edge that is perpendicular to the direction in which the mechanical equipment is operated.  See 29 CFR 1910.29(d) (29 CFR 1910 Subpart D).

k. Safety Monitoring System (SMS) (Administrative Control).  An SMS can only be used in combination with a passive, active, or additional administrative control (for example, warning line system (see para 21-8.i)).  The use of an SMS as fall protection method, when used independently, is prohibited.  See chapter 37 and figure 39-1 for exemption.  (21-8.k)