The rules all work together... so:

8.8. A certified pressure relief device [PRD] must be installed in each part of the pneumatics system where a different operating pressure is used (operating pressures separated by a pressure regulating device).
8.8.1 PRD(s) must have a rating of 1000 psi (68 bar) or 110% of the pneumatic component with the lowest €˜maximum working pressure€™ rating protected by that particular PRD, whichever is the lower.
8.8.2 Pneumatic systems employing pressures less than 50 psi or systems employing air compressors that have a maximum output pressure lower than the pneumatics component with the lowest €˜maximum working pressure€™ do not require a PRD.

2 Bar would not require a PRD as you can run up to 50psi (3.5 Bar) without a PRD.

The PRD need only be rated at 110% of your components rating, not your actual working pressure.
In other words, regardless of your actual running pressure, the PRD is rated for your components to protect them.

As you have stated, the low pressure circuit is already protected by an integral PRD in the regulator, usually set to 200psi.

Basically, although you are running 3 different pressures, you are only using 2 different ratings of components. And therefore only require 2 PRD.

Kane Aston
http://www.makerobotics.comhttp://www.makerobotics.com/