SECTION 4 Drill String Compensation System

401. General

1. The drill string compensation system can be categorized as active heave compensation and passive heave compensation.

2. Theory of operation is to be included in design plans and data, and is to include the backup brak- ing system and computer/control redundancy studies.

402. Drill string compensation system

1. The drill string compensation system typically consist of accumulators, air/nitrogen compressors, air/nitrogen dryers, compensators, control systems/consoles/panels, hydraulic cylinders, HPU, piping,

50 Guidance Relating to the Rules for the Classification of Mobile Offshore Drilling Units 2015

pressure vessels, sheaves, wire ropes, etc.

2. Component specific requirements

(1) Pressure retaining equipments are to be in accordance with Sec 8.

(2) Piping and hoses are to be in accordance with Ch 5.

(3) Materials are to be in accordance with Ch 3, Sec 1.

(4) Welding and non-destructive examination are to be in accordance with Ch 3, Sec 2.

(5) Load-carrying parts are to be in accordance with Ch 6, 603. 5.

(6) If the locking mechanism is in the load path, it is to be in accordance with Ch 6, 603. 5.

(7) Hydraulic and pneumatic cylinders are to be in accordance with Sec 8, 802.

3. Control systems for drill string compensation

(1) Electrical systems are to be in accordance with Ch 6, Sec 1.

(2) Control systems are to be in accordance with Ch 6, Sec 2.

(3) Any remotely-operated valve is to be equipped with an emergency backup power source.