March 12, 2013 mountainproductions

Insight from the Experts [Q+A]: Suspending loads with the D8+ – Guest Blog from CM’s Art Zobal

Mountain welcomes CM’s own Art Zobal as a guest contributor on our blog. For this post, Art shares some information on the D8+ and suspending loads above people with the unit:

D8 vs D8+

CM’s Lodestar D8 is a standard unit that is used in the majority of the applications, but you would need secondary support if you are going to suspend loads over people. The cost of the D8 unit would be much less since you do not have to derate the capacity by half and you only have one brake, instead of two.

With our new Lodestar, you can convert the standard D8 unit to a D8+ by adding a second brake, changing the clutch, and derating the unit with labels. An advantage to using the D8+ is if you are suspending loads above people, you do not need to have a secondary support. A good example of an application would be hanging line arrays that might need elevation changes. With the D8+, you would not have to send up a rigger to remove the secondary support, which would be saving time and money.

The D8+ defined by the European codes

In Europe, suspending loads above people is addressed by two European codes of practice: the SQP2 Chain Hoists (2010) and the VPLT SR2.0 (2004). Both of the codes of practice explain how the D8+ unit can be used to suspend loads above people without the need for secondary support. Even though this is a European requirement, it is being commonly requested for applications in the U.S. and when tours are going from the U.S. over into Europe.

The SQP2 defines the D8+ as follows:

The D8+ Electric chain hoist is constructed and dimensioned in such a way that the moving of overhead loads is possible, provided that no persons are standing under the load and that it is not necessary to install safety backups when the hoist is switched off.

The VPLT SR2.0 defines the D8+ as:

The D8+ is used to life loads during set-up and with the special characteristics of being able to hold loads at rest above people without using a secondary safety component.”

The D8+ can be achieved by having a minimum of 10:1 design factor and double brake. The cloth can be used as protection against overloading when the hoists are used for statically determinate loads.

The SQP2 discusses a statically determinate load system as:

• A load on individual electric chain hoists (point load)
• Distributed loads on two electric chain hoists
• Hinged, linked single span girders on more than two electric chain hoists
• Distributed loads on three electric chain hoists

While the load is moving, all personnel should be out from underneath the load. Once the load has been lifted, is in place, and the hoist is switched off, the load is “OK” to suspend above people without secondary support.

If you have any questions or would like more information about the D8+ or any of CM’s renowned chain hoists, please call us at 570 826 5566. We would love to help you choose your next chain hoist purchase, and our professional staff can assist you in assembling a complete rigging package.


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