HOW TO BUILD A ZIP LINE - SECTION ONE - CONCEPTS

SITE SELECTION

 

 

THE SITE SELECTION PROCESS MUST BE PERFORMED BY A COMPETENT ADULT AFTER ALL INSTRUCTIONAL MATERIAL HAS BEEN COMPLETELY REVIEWED AND UNDERSTOOD.

 

DETERMINE THE MOST ACCESSIBLE LOCATIONS FOR YOUR RIDER TO LAUNCH AND DISMOUNT. THIS WILL DICTATE THE INSTALLATION OF YOUR ZIP LINE. DEPENDING ON THE TERRAIN, THE DISMOUNT LOCATION MAY BE AT THE END OF THE ZIP LINE RATHER THAN THE LOW POINT OF THE CABLE. A PLATFORM MAY BE REQUIRED FOR ACCESS.

CLEAR THE ZIP LINE AVENUE OF OBSTRUCTIONS AT LEAST 7 FT. BELOW AND 5 FT. ON BOTH SIDES OF THE ZIP LINE. REMOVE LARGE ROCKS, LOGS, BRANCHES, SHARP OBJECTS, AND OTHER POTENTIAL HAZARDS.

SAFETY RIDING GEAR IS REQUIRED FOR ANY HEIGHT AND TERRAIN WHERE A FALL COULD RESULT IN INJURY.

 

 

ANCHORS

DID YOU KNOW?

A TYPICAL ZIP LINE CABLE CAN APPLY 800 TO 3,000 POUNDS OF HORIZONTAL FORCE TO AN ANCHOR WHEN LOADED.

DO NOT USE

BUILDINGS OR PLAYGROUND STRUCTURES (UNLESS SPECIFICALLY BUILT FOR ZIP LINES), LIVE POWER/TELEPHONE POLES, DEAD TREES OR STUMPS, TREES WITH ROT, DISEASE, STRUCTURAL CRACKS, EXCESSIVE LEAN, EXPOSED ROOTS, OR TREES IN BOGGY, WET, SANDY, LOOSE SOIL. THIS IS ONLY A PARTIAL LIST. YOU MUST USE YOUR GOOD JUDGMENT IN DETERMINING WHAT IS NOT AN APPROPRIATE ANCHOR POINT. IF IN DOUBT, CALL US TO DISCUSS.

TREES

TREE TRUNKS MUST HAVE A 12-INCH DIAMETER, MINIMUM, AT THE ATTACHMENT POINT. DO NOT ATTACH TO ANY LIMBS/BRANCHES OTHER THAN A CENTRAL TRUNK.

POSTS

WOOD POSTS MUST BE 12” DIAMETER, MINIMUM.

POSTS MUST BE SUNK 4 FT. IN GROUND, OR 10% OF POST LENGTH PLUS 2 FT. (WHICHEVER IS GREATER). SECURE WITH CONCRETE 6 INCHES THICK AROUND POST. SOIL MEDIA SUCH AS SAND, ROCK OR HIGH GROUND WATER ENVIRONMENTS MAY REQUIRE ALTERNATIVE INSTALLATION TECHNIQUES AND CONSULTATION WITH AN ENGINEER. 

GUY CABLES AND GROUND ANCHORS

POSTS WITH GUY CABLES AND GROUND ANCHOR POSTS MUST BE 8 INCHES DIAMETER, MINIMUM.

CABLE ATTACHMENT MUST BE 12 INCHES FROM TOP OF POLE, MINIMUM, AND AS CLOSE AS POSSIBLE TO ZIP LINE ATTACHMENT POINT.

INSTALL GUY ANCHOR POST AT A DISTANCE EQUAL TO OR GREATER THAN ATTACHMENT HEIGHT.

GROUND ANCHOR POSTS MUST BE SUNK 4 FT. IN GROUND, OR 10% OF POST LENGTH PLUS 2 FT. (WHICHEVER IS GREATER). SECURE WITH CONCRETE 6 INCHES THICK AROUND POST. SOIL MEDIA SUCH AS SAND, ROCK OR HIGH GROUND WATER ENVIRONMENTS MAY REQUIRE ALTERNATIVE INSTALLATION TECHNIQUES AND CONSULTATION WITH AN ENGINEER.

 

CLEARANCE

IT IS RECOMMENDED THAT THE ZIP LINE MAINTAIN AT LEAST A 7 FT. CLEARANCE OVER THE ENTIRETY OF THE ZIP LINE AVENUE WHILE SUPPORTING THE HEAVIEST RIDERS.

THE FOLLOWING TOOLS ARE RECOMMENDED FOR MEASURING ELEVATION CHANGE OF YOUR ZIP LINE SITE.

HELPFUL HINT: WE RECOMMEND FINDING A LANDSCAPE WITH A NATURAL SLOPE OF 3% TO 6%, (A 3 FT. TO 6 FT. OF DROP PER 100 FT.).

 

 

CABLE SLOP & SAG

 

CABLE SLOPE

THE MAXIMUM ALLOWABLE SLOPE IS 3% (3 FT. DROP PER 100 FT. OF DISTANCE) FOR ZIP LINES THAT WILL NOT UTILIZE A BUNGEE BRAKE (A STOP BLOCK IS NOT A BRAKING SYSTEM). THE MAXIMUM ALLOWABLE SLOPE IS 6% (6 FT. DROP PER 100 FT. OF DISTANCE) FOR ZIPLINES THAT UTILIZE A BUNGEE BRAKE.

ZIP LINE MUST NEVER EXCEED 6% (6 FT. DROP PER 100 FT. OF DISTANCE) RIDING SLOPE. HIGH SPEED COLLISION WITH END POINT MAY CAUSE INJURY OR DEATH.

CABLE SLAG

CABLE TENSION IS MEASURED BY CABLE SAG:

  • THE CABLE, WHEN BEARING A TEST WEIGHT, SHOULD SAG BELOW THE END WHERE CABLE IS ATTACHED.
  • THE SAG NEEDS TO BE APPROXIMATELY 2% OF ZIP LINE’S TOTAL LENGTH. (2 FT. PER 100 FT. OF CABLE )
  • THE SAG IS MEASURED AT THE CABLE’S LOWEST POINT.

DO NOT ATTEMPT TO RIDE YOUR ZIP LINE WITHOUT FIRST TESTING.

 

 

CABLE SLOPE & SAG WORKSHEET

 

USE THIS WORKSHEET TO HELP SET UP YOUR ZIPLINE. BY USING THESE STEPS YOU WILL BE ABLE TO DETERMINE THE LENGTH, SLOPE, SAG, ELEVATION CHANGE (IF ANY) IN YOUR LANDSCAPE AND YOUR STARTING AND ENDING ANCHOR.

1. MEASURE THE DISTANCE BETWEEN START AND END ANCHORS. USING "FEET" ENTER YOUR MEASUREMENT IN BOX 1. THIS WILL BE YOUR LENGTH. (ROUND UP TO NEAREST FT.)

2. CALCULATE THE SLOPE OF THE ZIP LINE AND ENTER IN BOX 2.

  • a. MULTIPLY BOX 1 BY .03 IF YOU ONLY HAVE A STOP BLOCK
  • b. MULTIPLY BOX 1 BY .06 IF YOU HAVE A BUNGEE BRAKE

3. CALCULATE THE SAG.

  • a. MULTIPLY BOX 1 BY .02 AND ENTER THE ANSWER IN BOX 3.

4. MEASURE AND CALCULATE ELEVATION CHANGE. IF GROUND IS LEVEL, ENTER “0” IN BOX 4C. IF NOT, USE A SIGHT LEVEL AND HAVE A FRIEND ASSIST IN MEASURING. 

DETERMINE YOUR SIGHTING HEIGHT AND ENTER IT IN BOX "4B"

SIGHT A LEVEL LINE TO YOUR END ANCHOR THROUGH YOUR SIGHT LEVEL. TILT SIGHT LEVEL UP OR DOWN UNTIL BUBBLE ALIGNS WITH CENTER CROSSHAIRS. FIND A LEVEL LINE AND HAVE YOUR FRIEND MARK THE END ANCHOR. MEASURE THE HEIGHT OF THE MARK FROM THE GROUND AND ENTER IN BOX “4A”. A-B=C (ELEVATION CHANGE) – NOT TO BE CONFUSED WITH CABLE SLOPE.

HELPFUL HINT: AS AN ALTERNATIVE TO A SIGHT LEVEL YOU CAN USE AN ALTIMETER APP

5. DETERMINE YOUR ENDING ANCHOR POINT HEIGHT BY ADDING BOX 3 PLUS 7 FT. AND ENTER THE ANSWER IN BOX 5. THIS IS THE HEIGHT OF YOUR ENDING ANCHOR POINT

6. TO DETERMINE THE HEIGHT OF YOUR STARTING ANCHOR POINT, ADD BOX 2 AND BOX 5 TOGETHER THEN SUBTRACT BOX 4C. ENTER THE ANSWER IN BOX 6. THIS IS THE HEIGHT OF YOUR STARTING ANCHOR POINT.

 

 

 

 

 

PRINT WORKSHEET

 

 

INSTALLATION EXAMPLE

BROCK’S BACKYARD IS PERFECT FOR A ZIP LINE. HE ORDERED A 200-FT LINE AND IN ORDER TO INSTALL IT, HE NEEDS TO FIGURE OUT WHERE TO ANCHOR THE CABLE ON EACH OF HIS TWO TREES. SO HERE’S WHAT HE DID. FIRST, BROCK READ THROUGH THE ENTIRE MANUAL THE EVENING BEFORE HE PLANNED ON SETTING UP HIS ZIP LINE.

BOX 1: THE NEXT DAY HE PACED OFF THE DISTANCE TO MAKE SURE HE KNOWS THE EXACT DISTANCE. THE DISTANCE IS 180-FT. HE FILLS IN BOX 1 = 180

BOX 2: NEXT, HE FIGURED OUT THE AMOUNT OF SLOPE HE WILL NEED. SINCE HE PURCHASED A ZIP LINE THAT ONLY INCLUDED A STOP BLOCK, HIS CALCULATIONS WILL BE FOR A 3% SLOPE. WHIPPING OUT HIS SMART PHONE HE MULTIPLIES 180 X 0.03 AND GETS 5.4, WHICH HE ROUNDS TO THE NEAREST WHOLE NUMBER AND ENTERS 5 IN BOX 2.

BOX 3: USING HIS LENGTH OF 180 FROM BOX 1 HE MULTIPLIES IT BY 0.02. HIS ANSWER WAS 3.6 WHICH HE ROUNDS TO THE NEAREST WHOLE NUMBER 4 AND ENTERS IT INTO BOX 3.

BOX4: TO FIGURE OUT HOW MUCH HIS YARD ELEVATION CHANGE IS BETWEEN THE TWO ANCHOR POINTS HE ORDERED A SIGHT LEVEL. HE IS SIX FEET TALL, SO HE PENCILS 6 IN BOX 4B, NEXT HE LOOKS THROUGH THE SITE LEVEL UNTIL THE BUBBLE LINES UP WITH THE CENTER CROSSHAIRS ON THE END ANCHOR TREE. THERE HAPPENS TO BE A NICE BRANCH THAT HE CAN IDENTIFY EASILY WHICH WILL BE WHAT HE WILL USE FOR A MARK. HE HIKES TO THE END ANCHOR TREE, SETS A LADDER AGAINST THE TREE AND CLIMBS UP THE LADDER WITH A TAPE MEASURE. HE MEASURES FROM THE GROUND TO HIS MARK, WHICH WAS A NICE BRANCH. THE TAPE MEASURES 14-FT. HE PENCILS IN 14 IN BOX 4A AND THEN CALCULATES WHAT BOX 4C IS. [14 - 6 = 8] AND HE PENCILS 8 IN BOX 4C.

JUST FOR THE FUN OF DOUBLE CHECKING HIS FIGURES, HE DOWNLOADS AN ALTIMETER APP ON HIS SMART PHONE. STANDING AT THE BASE OF THE START ANCHOR TREE HE TAKES THE FIRST MEASUREMENT WHICH IS 1743 FT. FROM SEA LEVEL. HE JOTS DOWN THAT NUMBER WHILE STRIDING OVER TO THE END ANCHOR TREE. TAKING ANOTHER MEASUREMENT ON HIS APP AT THE BASE OF THE END ANCHOR TREE, THE READING SHOWS 1735 FT. FROM SEA LEVEL WHICH HE PENCILS BELOW THE FIRST FIGURE. CALCULATING THE DIFFERENCE BETWEEN THESE TWO MEASUREMENTS WILL BE THE ELEVATION CHANGE BETWEEN HIS TWO ANCHOR POINTS AND THIS CAN BE ENTERED INTO BOX 4C.

1743 ft. - 1735 ft. = 8ft.

WITH ALL OF HIS PHYSICAL MEASUREMENTS COMPLETED, HE SITS DOWN ON HIS BACKYARD DECK AND FILLS OUT THE REST OF HIS WORKSHEET.

BOX 5: TO CALCULATE HIS ENDING ANCHOR HEIGHT [BOX 3 + 7 FEET = BOX 5] 4 + 7 FEET = 11 FOR THE END ANCHOR HEIGHT.

BOX 6: TO CALCULATE HIS STARTING ANCHOR HEIGHT [BOX 2 + BOX 5] – [BOX 4C ] = [BOX 6 ] [5 + 11 = 16]– [8] = 8 FOR THE START ANCHOR HEIGHT.

SAMPLE WORKSHEET

 

 



 

NOW BROCK IS READY TO MOVE ON TO HIS NEXT STEP.

 

 

PRINT WORKSHEET