CONSTRUCTION SAFETY MAGAZINE Summer 20074

Lifeline rope

Lifeline ropeBy Jennifer Coccimiglio, Writer, and Brian Varrasso, Project Coordinator, CSAO

When you’re wearing fallprotection, you trust your life toyour lifeline. Make sure it canactually save your life. Make sureit’s the right kind of rope.

Some types of rope are better thanothers for lifelines—and sometypes should never be used forlifelines at all. This article will helpyou make informed decisionswhen you’re selecting rope forlifelines.

We’ll look at two aspects of rope:its material and its design.

Rope material

Nylon, polyester, polypropylene,and polyethylene are commonmaterials used when making rope.For lifelines, nylon, polyester, anda polypropylene/polyethylene

blend are good, but rope made ofonly polypropylene is not.

Nylon

Nylon is a good choice for a lifelinebecause of its strength anddurability. It is usually moreexpensive than a polypropylene/polyethylene blend.

Polyester

Like nylon, polyester is also a goodchoice for a lifeline.

Polypropylene/polyethyleneblend

A good choice for a lifeline is apolypropylene/polyethylene blend.The polyethylene makes the ropemuch stronger than one made withpolypropylene only. It also makesthe rope more resistant to abrasionand ultra-violet (UV) radiationthan pure polypropylene.

The blend is less expensive thannylon and only slightly moreexpensive than polypropylenealone.

Polypropylene only

Do not use polypropylene rope forlifelines. Here’s why.

At a standard 5/8” diameter, apolypropylene rope will usually notmeet the 6000-pound strengthrequirement in CSA (CanadianStandards Association) standardZ259.2.1, Fall Arresters, VerticalLifelines and Rails.

To meet the strength requirement,the manufacturer will often makethe diameter slightly larger than5/8”. But if you use it in a ropegrab, the extra diameter will meanmore wear and tear, and the ropewill be damaged quickly.

Polypropylene also degrades quickerthan nylon and other materialswhen exposed to ultra-violet (UV)radiation and weathering. After afew months of the sun beatingdown on it, a polypropylene ropecan lose a significant amount of itsstrength.

For these reasons, do not usepolypropylene rope for lifelines.

This three-strand twisted rope is made from a polypropylene/polyethylene blend.The different-coloured strand indicates that the material is a blend.

CONSTRUCTION SAFETY MAGAZINE Summer 2007

Lifeline rope

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Rope design

The materials listed on theprevious page can be made intorope according to several designs.There are generally three styles ofrope design: twisted, kernmantle,and braided.

There are advantages anddisadvantages to each design. Hereare the details.

Twisted design

Twisted rope is an acceptabledesign for vertical lifelines, and it’scertainly the most common. But atwisted design makes the ropevulnerable to abrasion, whichdecreases total rope strength.

Twisted rope is more likely thanbraided rope to get caught onthings and rip or tear.

Twisted ropes are often made froma polypropylene/polyethyleneblend. The design is usually three-strand twisted. Generally a twistedpolypropylene/polyethylene blendrope intended for safetyapplications will have a singlestrand of a different colour toshow that the material is a blendrather than just polypropylenealone. (See photos on page 4.)

If all three strands are the samecolour, the rope is probably a

Kernmantle rope is very durable. Thefibres in the core run straight. All ofthe rope’s strength is in the core, whilethe braided sheath protects the core.

Continued on page 6

Do not use utility rope for lifelines.�

utility rope. Do not use utilityrope for lifelines. Utility ropes areoften spliced, which furtherdecreases their strength. Lifelinesmust be made of continuousunspliced rope.

Kernmantle design

Kernmantle rope is the idealchoice for most lifeline situations.It consists of an inner core ofsynthetic fibre filaments runningstraight (they’re not twisted orbraided), and an outer braidedsheath which surrounds andprotects the filaments.

When attached to the rope, theload is held by the strength of theinner core filaments, while theouter sheath only protects therope’s core from dirt, UVradiation, and abrasion. Thesturdy, sheathed design ofkernmantle rope can be adisadvantage in certainapplications (such as suspendedaccess), because it’s less flexiblethan other rope.

Although kernmantle rope issignificantly more expensive thanother rope, it usually has a longerservice life.

Braided design

Braided rope is more resistant toabrasion than twisted rope, so itwill not tear or rip as easily.

Solid braid design

Solid braid ropes are used mostlyfor window washing because theyare very flexible. This allows themto be twisted around suspensiondevices.

Lifeline rope

CONSTRUCTION SAFETY MAGAZINE Summer 20076

Lifeline rope

Unlike kernmantle rope, however,all strands give the rope itsstrength. This means that anywear, cuts, or variations in size willdrastically decrease the rope’sstrength.

Double braid design

Double braid ropes have a braidedcore protected by an outer braidedsheath. This construction gives therope good strength and the outerbraid makes it resistant toabrasion.

With this design, however, theouter and inner braids can movefreely and separately. This is aproblem because with double braidrope, both the core and the sheathsupport the weight of the load.(This is not the case withkernmantle rope.)

If the core and sheath in double-braidrope are not aligned, the rope loseshalf of its strength. This photo showshow the sheath can bunch up.

CSAO thanks Rob Ludwig fromCancord Inc. for providinginformation and rope samples.

Continued from page 5

�A solid braid rope is very flexible.It can stretch under load.

A double braid rope consists of abraided sheath covering a braidedcore. Both the core and sheathsupport the load, so they must bealigned. If the sheath bunches up, youdecrease the rope’s strength by 50%.

Both the core and the sheath mustbe aligned for the rope to maintainits total strength. Often, the outerbraid becomes caught on somethingand bunches up, which decreasesthe rope’s strength by 50 percent.When the sheath bunches up, theinner core supports all of the load.Unless you can ensure the twobraids remain in the correctposition, this rope is not suitablefor safety applications.

Stretch

Other aspects of rope affect itssafety performance, such as stretch.

Some ropes stretch more thanothers when subjected to a load.

Twisted and braided ropes stretchsignificantly while kernmantleropes stretch very little. Wetconditions can make some ropesstretch more than others.

You need to take stretch intoaccount when calculating possiblefree-fall distance. (See “Lifelineinspection” on the next page.)

Always check with themanufacturer to learn theadvantages and disadvantages of therope you’re considering.

CONSTRUCTION SAFETY MAGAZINE Summer 2007

Lifeline inspection

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Lifeline inspectionInspect your lifeline and lifelinesetup before each use.

1. Make sure you have the righttype of rope for a lifeline (seearticle on page 5).

2. Look for the CSA(Canadian StandardsAssociation) logo.Lifelines must beCSA certified. The logo willbe on the rope, or on the reelif it came in bulk. If the ropeis not CSA certified, do notuse it for lifelines.

3. Inspect the rope to see if it isin good condition. If you findany of the following things,the lifeline is unsafe.

� Tears or cuts.

� Unequal strand size orshape variations.

� Discolouration.

� Broken or loose strandsinside the rope (untwist therope and check inside).

� Accumulated powder ordirt inside the rope(untwist the rope andcheck inside).

� Loose thimbles (ensure thatthimble splices are in goodcondition).

� Decreased elasticity (a ropeloses elasticity especially if ithas been subjected to aload).

4. Never reuse a lifeline that hasbeen used for any otherpurpose. Throw away a lifelinethat has stopped a fall unless ithas been recertified by themanufacturer.

5. A vertical lifeline must be usedby only one person at a time.

6. A vertical lifeline must reachthe ground or a level aboveground where you can safelyexit if your fall is arrested.

7. Ensure that therope grab iscompatible withthe type of ropeyou are using foryour lifeline.

Check the rope-grabmanufacturer’s instructions fora compatible lifeline.

8. Consider the distance to theground or level below whendetermining where you attachyour rope grab. You do notwant to strike a lower surfaceor hit an object before your fallis arrested. Calculate how long

�

�your lanyard will extend. Also,lifelines stretch under load. TheCSA standard allows up to22% stretch. Find out from themanufacturer how much yourrope will stretch.

Take all of these factors intoaccount when calculatingdistances.

9. A vertical lifeline must have apositive stop—a knot or deviceat the end of the rope toprevent the rope grab fromslipping off the end.

10. Ensure that the lifeline isprotected from abrasive orsharp edges.

11. Store lifelines

� in a dry location

� out of direct sunlight

� away from sharp objects

� away from corrosivechemicals.

Hitting the ground while tied off.