CoatingsPro Magazine

JAN 2017

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Page 34 of 116

34 JANUARY 2017 COATINGSPROMAG.COM alterations, repairs, impact loading, and welding or cutting operations are made above the net. Nets that show mildew, wear, damage, or deterioration that might affect their strength shall be immediately removed from service for complete inspection and repair. Job Testing Nets and suspension systems should be tested after each installation, alter- ation, or major repair before being returned to service and at six-month intervals thereafter. If a net is more than 18-months old, a reasonable test interval should be established. Job tests differ slightly from prototype tests conducted by the manufacturer. For nets of normal size, the American National Standards Institute says tests should consist of dropping a 400-pound (181.4 kg) bag of sand not more than 30 inches ±2 inches (76.2 cm ±5.1 cm) in diameter from a height of approximately 25 feet (7.6 m) above the net into the center of the net. A job should be considered satis- factory if there are no broken members and no significant distortion of net pattern or the suspension system. Care, Maintenance, and Storage Care, maintenance, and storage of safety nets should be in accordance with the net manufacturer's recommendations with due attention being given to the factors affecting the safety aspects offered by the net. ese factors include: • Sunlight. This affects all fibers, including those commonly used. All nets not in use should be protected from direct and indirect sunlight. • Abrasion. There is no test that will predict the life of a net under the wide variety of abrasion conditions that may be encountered. The adverse effects of abrasion should be constantly borne in mind. Nets should not be dragged over the ground or other rough surfaces. • Sand. Embedded sand cuts fibers, reducing the strength of nets. Care should be taken to keep nets as clean and free of sand, or other abrasive materials, as possible. • Rust. Prolonged contact with rusting iron or steel can cause significant degradation and loss of strength. Nets should not be stored in metal containers that are rusty and should be suspended on non-rusting hooks. • Airborne contaminants. Extremely high concentrations of many chemi- cals can adversely affect the strength of nets. Where high concentrations may exist, the chemicals should be identified and the concentrations measured. The effect on the net material involved should be deter- mined by test if it is not known. Debris shall be removed from safety nets at least daily. Repairs to nets should be made promptly and properly by qualified personnel. Defective ropes should be satisfactorily spliced and replaced with new ropes. Dirt and grit act as abrasives and should be removed by washing with clean water. After washing, manila ropes should be dried and re-lubricated with oil recommended by the rope manufacturer. Proper storage of nets is essen- tial. Nets may be stored in dry/shaded areas; they may be hung or folded on pallets. Good air circulation is neces- sary. Confined dampness is detrimental to manila rope but does not affect synthetic ropes. All types of nets should be protected against damage from heated surfaces, sharp materials, fungi, rodents, and falling objects. Synthetic fiber ropes are not affected by mildew, and the resis- tance to mildew by untreated manila rope is good except in humid climates. erefore, a mildew-resistant treat- ment of manila rope is recommended. Treatment can be applied during manufacturing, or nets can be dipped in a fungicide solution at the jobsite. Fire Prevention Manila and synthetic rope nets can be seriously damaged by fire. erefore, combustible material should not be allowed to accumulate in suspended nets. W hen riveting, welding, or burning is done above nets, they should be under constant observation. Serious damage has resulted when welding slag has fallen into nets piled or rolled up under construction work. Nets hung vertically when stored are least exposed to these overhead hazards. Manila rope is fire-resistant to a degree and does not support combustion under normal conditions. However, fire-retardant treatments have not proved practical when nets are exposed to the weather. Furthermore, application of fire-retardants to synthetic ropes is of no value, because these ropes will melt instead of burn when exposed to heat. Best Practices A lthough the use of safety netting is used in the construction industry, including by coatings contractors, not all users may be following or aware of best practices. For the safety of people below and above the netting, it is imperative that these guidelines be followed. CP Editor's note: This article is an excerpt from the National Safety Council 's Data Sheet 609 titled, "Safety nets: Fall protec- tion for the construction industr y." To read the rest, head to Dr. Wes Scott has more t han 30 years' e x per ience in t he bio-med ica l , eng ineer ing , env ironmenta l , and occupat iona l safet y and hea lt h f ield s. Whi le work ing w it h t he U. S. A r my Cor ps of Eng ineers and t he Federa l Emergenc y Management A genc y, he prov ided leadership and technica l d irec- t ion for d isaster assessment and rel ief; developed st r uct ura l t heor ies and solut ions; conducted t ra in- ing ; and implemented safet y prog rams in more t han 20 locat ions. Dr. Scott hold s a B. S. in Business Management f rom t he Universit y of Mar yland ; an M . S. in Civ i l Eng ineer ing f rom Howard Universit y ; and a Ph.D. in Eng ineer ing Management f rom t he Universit y of Mar yland . For more infor mat ion, contact: t he Nat iona l Safet y Counci l , w w Safety Watch

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