Machine Safety requirement for Filter presses

[mehdi1351]

Hello all,
As I am not familiar with US compliance requirement for the machine safety, would appreciate if anyone can assist me on the following:
1- Does an E-stop button on the local control panel is enough to stop the machine or should we install a pull-cord or Trip-wire on the both side of filter press and link it into the PLC to stop the machine?
2- Does movable guards required on the hydraulic power pack? Currently many manufacturer doesn't propose any movable guards interlock to the filter-press closed limit switch. The safety concern is, when the filter-press closed (under high pressure hydraulic) and if someone release the hydraulic lever (i.e open the filter press), then the high pressure liquid can splash and make a safety concern for someone nearby the device.
3- Generally is there any standard I should comply with for machine safety in US?

 

[petersonra]

You need to do a risk assessment to determine the requirements.

 

[mehdi1351]

You need to do a risk assessment to determine the requirements.

We definitely do, but I would have thought that there might be some fixed requirement (minimum requirement) dictated by OSHA or any similar US standard for the Filter presses.

 

[petersonra]

We definitely do, but I would have thought that there might be some fixed requirement (minimum requirement) dictated by OSHA or any similar US standard for the Filter presses.

Take a look at nfpa79.

The problem with your question is that it requires a lot of detailed knowledge of your equipment that you probably can't supply publicly. And even then no one could give you anything other than a best guess as to what you need.

You should probably also be compliant with UL 508a.

I think after you give both of those standards a good look through you will find some of the answers at least to your questions.

 

[BillyMac59]

An e-stop's primary purpose is personnel safety. As such, it should be within easy reach of the machine operator. The risk assessment will include protecting the worker at all stages of interaction with the machine. This means not just the operator but cleaning and maintenance staff, among others. Never rely on a standard PLC for your safety circuit. Independent safety relays and/or safety PLCs are the norm. You can add an input to your standard PLC to notify of a shutdown.

 

[Jraef]

In general though, unlike other parts of the world, there are not a lot of SPECIFIC regulations around machine safety, it’s mostly a generalization in that OSHA regulates EMPLOYERS, dictating that they have and maintain a safe workplace but for the most part, OSHA does not normally dictate HOW that is achieved. So on a given machine, it’s incumbent on the employer using the machine to identify safety risks to their employees (hence the “risk assessment”) and make sure they are addressed. There are a few regulations as to minimums and others for specific machines and systems, ie punch presses and belt conveyors for example, but the concept of “machine safety controls”, although highly ENCOURAGED, is not regulated. At least not yet.