Whenever a rope is used, it is important to adhere to the guidelines set forth by EN14960, which specify an anchor system requirement of 167kg per anchor point.
To meet this requirement, it is necessary to select a rope with a final strength of 167kg or higher. This ensures that the rope is capable of providing the necessary support and security for the inflatable structure.
Additionally, it is crucial to consider the impact of knots on the breaking strain of the rope. Knots can reduce the strength of the rope by up to 50%, depending on the type of knot used. To err on the side of caution, it is advisable to assume a worst-case scenario and account for a 50% reduction in strength due to knots.
To provide an extra layer of safety, it is recommended to round up the strength requirement from 167kg to 200kg. This additional safety margin helps ensure that the rope can withstand the forces exerted on it and provides added peace of mind.
By following these guidelines and taking into consideration the reduced strength caused by knots, we can ensure that the anchor system is properly secured and capable of withstanding the necessary forces. This attention to detail and commitment to safety is essential in providing a secure and enjoyable experience for users of inflatable structures.
Calculations
Given that you are likely to tie one knot at each end as a minimum, we would need to multiply the rope by calculating backward by using the chart below for a bowline.
Example 1 - A slide rope with one knot in each end.
14mm rope = 4,368kn for a bowline knot
4,368 / 50% for knot 1 = 2184kn
2184 / 50% for knot 2 = 1092kn
The total breaking strain would be 1092kn.
This is overkill for a simple rope and we can choose a much smaller one.
Example 2 - A slide rope with 4 knots in total.
10mm rope = 2,548kn for a bowline knot
2,548 / 50% for knot 1 = 1274kn
1274 / 50% for knot 2 = 637kn
637 / 50% for knot 3 = 318.50kn
318.50 / 50% for knot 4 = 159.25kn
The total breaking strain would be 159.25kn.
This rope would fall short of the 167kg requirement, let alone wit a 200kg safety margin.
I have included an example working chart below to help you select the correct operational strain of rope.
Summary
Please keep in mind that the rope system is of equal importance to selecting the appropriate anchors and sandbags. All calculations provided are specific to bouncy castles and slides and are applicable within the UK's 24mph wind limit.
It is crucial to remember that all ropes must be securely fixed at a 45-degree angle to the slide at all times to ensure maximum strength. This requirement is specified by EN14960, which outlines safety regulations for inflatable play equipment.
Based on our experience, we have found that polypropylene ropes tend to be the most suitable choice for inflatables. These ropes offer the necessary strength and durability required for secure anchoring. You can easily find 12mm polypropylene ropes through various online sources. We recommend visiting the following link for a convenient search:
https://www.google.com/search?q=12mm+polypropylene+rope&rlz=1C1CHBF_enGB1058GB1059&sxsrf=APwXEdeVRGC8q5jpqDxF3rG8M-dEr0FR3Q:1685611625615&source=lnms&tbm=shop&sa=X&ved=2ahUKEwit4rHR4KH_AhUyiP0HHRA7A9YQ_AUoAXoECAEQAw&biw=1920&bih=929&dpr=1
By utilizing high-quality ropes, properly fixed at the specified angle, you can ensure the stability and safety of your inflatable structures.
I hope this helps and I look forward to hearing from you soon.