Debra Schug, Contributing Writer
The law of gravity is pretty simple; what goes up, must come down. But, in a material handling facility, gravity mixed with an accidental push of product off a top shelf or rack in an unprotected storage area can mean disaster. Installing safety netting to protect product and people before an accident happens is crucial. This article will go over safety netting design, materials and installation practices that can make a big difference in industrial workplace safety.
The Need for Netting
There is a popular misconception that when items are placed in a properly installed storage rack, they are solidly stored in a static condition. However, according to recent statistics from OSHA, there are over 50,000 “struck by falling objects” injuries in the country every year. So, the evidence shows those items stored aren’t always kept perfectly in place.
OSHA and the American National Standards Institute (ANSI) have regulations with which facilities must comply, if they store items. For example, OSHA 1926.501(c )(1) says toeboards, screens or guardrail systems must be erected to prevent objects from falling from higher levels, if there isn’t a canopy structure or a barricade in place.
In a webinar hosted by the Protective Guarding Manufacturers Association (ProGMA), a product group within MHI, Eddie Murphy, President of Spaceguard Products, said most accidents typically occurring with overhead storage systems relate to falling product.
“Whether you are storing materials 10 or 35ft off the ground, you should be concerned with how the materials are contained on those storage systems to prevent injuries or costly damage,” said Murphy.
With an estimated 80% of storage items contained on pallet racks in material handling facilities, these items are at risk of falling and must be properly secured. Safety mesh netting is a common solution and is available in a variety of materials, including polypropylene, nylon or extruded plastic netting.
Netting is not the only choice for securing stored items; however, it is a particularly good solution to not only keep workers safe by preventing falling product off of racking systems, but also to protect the items themselves from potentially being damaged in the event of an accident.
“Nylon netting creates a barrier that prevents products from falling and is flexible enough to prevent product from being damaged should it come into contact with the netting,” said Russ Schirmer, Director of Sales for Carron Net Company, Inc.
He said although nylon netting is lightweight, it is very strong with mesh load ratings from 250-5,000lbs. However, it can be cut by sharp objects, so wire mesh is a better choice for storing items with sharp edges.
Multiple Places for Netting
If storage areas are above or near work areas, safety netting is a must-have to keep product from falling into these places and onto workers. ANSI A10.11-1989 (R1998) states “Neither public traffic nor workers shall be permitted underneath a work area unless they are protected from falling objects. In cases in which personnel nets are used, they shall be line with debris netting with a mesh of size and strength sufficient to contain tools and materials capable of causing injury.”
Safety netting can also be used in machine guarding to protect workers from accidentally coming in contact with dangerous equipment or for security reason. Safety fences or screens can also be used, however, netting can be a good lower cost option and is easier to install.
“When using a smaller mesh, (companies) can keep idle hands from tampering with or taking items,” said Schirmer. “When the mesh is damaged or removed, they know they have a problem.”
In addition, netting can also be used to keep product securely in its place and not shifting to inconvenient places, like the flue space between back-to-back racks. When positioned on the back side of a pallet rack, netting can prevent product from falling behind racks onto the floor below or from lodging in the open space.
“Usually nets are attached directly to the back of racks, but because pallets are sometimes deeper than the racks they go on, an offset netting system is used to allow for pallet allow for the overhang,” said Schirmer. “That said accessible rack netting can also be used on the front side of racks to protect workers in areas prone to seismic activity or just as a safety precaution.”
Netting for Conveyor Guards
Many newer material handling facilities and those trying to fit as much as possible within their existing footprint have installed overhead conveyors to fully use the vertical space. However, as one can imagine, having product flowing over the heads of workers on the floor below via conveyors can be a hazard if there isn’t the proper guarding around them.
In fact, OSHA regulations covers conveyors in 1926.555(a)(5), which states, “where a conveyor passes over work areas, aisles, or thoroughfares, suitable guards shall be provided to protect employees required to work below the conveyors.”
To be in compliance with OSHA and to protect workers and product, safety netting can be installed on the sides and below the overhead conveyors to prevent any product from falling. According to Schirmer, conveyor catch netting has options for U-shaped netting surrounding the conveyor, side netting or netting underneath. Nylon nets specifically are useful in this application, because they can minimize the damage to a falling product.
“Netting, by design, absorbs the kinetic energy of a falling item, whereas a hard-surface guard may otherwise damage the product during its fall,” said Murphy.
As mentioned above, installing safety netting is typically lower in cost and easier than rigid safety fencing or screens. For example, polypropylene plastic mesh can either be precut at the manufacturer’s factory or can be produced in custom sizes. Additionally, the netting can also be trimmed on site to fit unique and challenging spaces.
One best practice of installing safety netting is to use cable ties. However, a good quality cable tie, made from durable material such as nylon resin, is essential to achieve the best protection performance of the safety netting. Also, when choosing cable ties, the length should be long enough to be wrapped around the rack or frame.
Installation also typically involves using shears, and since the edges of the mesh can be sharp, work gloves are recommended as well. Moreover, clips made of polypropylene or molded PVC clips can be used to secure netting wrapped around wires and posts.
In order to install netting flush to rack systems, the netting sheet should be placed on the floor next to the rack to be covered. The netting should then be pulled to the top of the rack and wrapped as snug as possible. The wrapped end should then be tied in the center, as well as frequently from top to bottom of the netting, to keep it aligned tightly with the racking. Excess material can then be trimmed with shears.
Another best practice of installing safety netting is to mount it to a pallet stop. These steel stops prevent pallets from being pushed off shelves as well as prohibits the pallets from touching the netting when a pallet overlaps the rack beams. Pallet stops should be off-set a few inches behind shelves, and the netting can then be attached to the pallet stops to safely and securely contain the product.
No matter how the netting is installed, one of the benefits this type of safety system provides is flexibility. Netting can be easily moved or readjusted by cutting and reinstalling it with ties. WMHS