Ukukhetha phakathi kwe-polyester flat sling kanye nesihlilingi esiyisicaba senayiloni akuyona indaba yokuthi enye 'ingcono' kunomunye—kuncike ngokuphelele endaweni yesicelo. Zombili izinto ezisetshenziswayo zabelana ngemikhawulo efanayo yomthwalo wokusebenza kanye nebanga lokushisa (-40°C kuya ku-100°C) ngaphansi kwe-EN 1492-1, kodwa zihluke kakhulu ekwelulweni, ukumelana namakhemikhali, nokusabela komswakama. Inayiloni inweba ngo-6–10% ngomthwalo olinganiselwe futhi imelana nama-alkali kodwa ibhujiswa ama-asidi. I-polyester yelula kuphela u-3-4% futhi imelana nama-asidi kodwa yonakaliswa ama-alkali. Lo mhlahlandlela uhlinzeka ngokuqhathanisa okuningiliziwe ukuze usize onjiniyela nezingcweti zokuqola ukukhetha okufanelekile kwesihlilingi esiyisicaba ngezimo zabo zokusebenza ezithile.
Ukwazi ukuthi kunini lapho kushintshwa izihlilingi eziyisicaba kubalulekile ukuze kuqiniswe ukuphepha kanye nokuthobela imithetho. Amazinga omkhakha we-ASME B30.9 kanye ne-EN 1492-1 achaza amazinga amabili okuhlola—ukuvamile (ukusetshenziswa nsuku zonke noma ngaphambi kwesikhathi) kanye nezikhathi ezithile (zonyaka noma phakathi nonyaka)—ngalinye linemibandela ethile yokunquma ukuthi isihlilingi kufanele sisuswe nini enkonzweni. Lo mhlahlandlela uchaza umehluko phakathi kokuhlolwa okuvamile nokwezikhathi ezithile, unikeza izinhlu zokuhlola ezinemininingwane ngayinye, futhi uveza indlela yokuthatha umhlalaphansi ebangela ukushintshwa kwesihlilingi. Kubaphathi abakhwabanisayo, abaphathi bezokuphepha, nabaqhubi, lesi yisithenjwa esisebenzayo sokugcina i-inventory ye-sling ephephile.
Isihlilingi esiyisicaba asigcini nje ngokuphakamisa umthwalo—siyawuvikela. Indawo ebanzi, eyisicaba yewebhu isakaza isisindo somthwalo endaweni enkulu, inciphisa ngokuphawulekayo ingcindezi kunoma iyiphi indawo. Lona umgomo oyisisekelo wefiziksi ngemuva kwezihlilingi eziyisicaba: Ingcindezi = Force ÷ Indawo. Ngokwandisa indawo yokuxhumana, izihlilingi eziyisicaba zinciphisa ingozi yokulimala kwendawo, amazinyo, nokuchotshozwa—okuwenza kube yinketho ekhethwayo yokuphakamisa izinto ezithambile, eziqediwe, noma ezilimele kalula. Lo mhlahlandlela uchaza i-physics yokusabalalisa ingcindezi, uqhathanisa izihlilingi eziyisicaba nezinye izixazululo zokuphakamisa, futhi unikeza isiqondiso esisebenzayo sokukhetha ububanzi obufanele besihlilingi sohlelo lwakho lokusebenza.
Umthetho we-1/10 uyisimiso esiqondile kodwa esibalulekile sokuthatha umhlalaphansi kuma-slings ayisicaba: uma ukuguga kunciphisa ububanzi bewebhu ngo-1/10 noma ngaphezulu, isihlilingi kufanele sisuswe enkonzweni. Lo mthetho ucaciswe ku-EN 1492-1 futhi ubonwa yi-ASME B30.9 njengenkomba eyinhloko yokuguga ngokweqile. Lo mhlahlandlela uchaza ukuthi umthetho we-1/10 usho ukuthini, indlela yokulinganisa ububanzi bewebhu ngokunembile, kungani lo mkhawulo ukhethiwe, nokuthi ungawusebenzisa kanjani ekuhlolweni kwansuku zonke. Kubaphathi bokukhwabanisa nochwepheshe bezokuphepha, ukuqonda lo mthetho olula kungavimbela ukusetshenziswa kwezihlilingi ezigugile eziyingozi.