Excavation

 

EXCAVATION  

Contractors shall refer to ADNOC HSE Standard, HSE-OS-ST15 for details and necessary compliance.  

Minimum Requirements  

Contractors shall conduct excavation activities by utilizing competent resources and implement necessary  precautions .

Mechanical excavations shall not be used in the proximity of service equipment or facility as per the distance specified in the ADNOC Group procedures. All excavation equipment shall be inspected and approved by ADNOC Group representatives.

Any excavation shall be adequately protected by shoring/sloping/benching if people are required to work in the excavation and the depth is more than 1.2 m. Shoring must be designed by a qualified person.   

Contractors shall implement ADNOC Group permit to work system for excavations. Confined Space permit/certificate shall be obtained in line with ADNOC Group procedures when the excavation depth exceeds the limit set by the ADNOC Group. Any work in excavation after a severe weather condition like rain, heavy wind etc.

shall be permitted only after an inspection by a competent person.  

Contractors shall implement the requirements of ADNOC Group procedures and safe work instructions for Trenches and Excavations.  

Excavations shall be properly marked with proper signs and barricades and means of escape and rescue must be identified during design. 

Proper access into excavations one meter deep or more such as ladders or stairs shall be provided. Crossovers and access to be provided at stipulated intervals along the entire length of the excavation as applicable.

Existing underground installations shall be marked on site prior to any excavation. Effort shall be made to determine if there are existing underground facilities/ installations.  

Contractors shall ensure that all Formwork supports are constructed to ADNOC Group approved standards.  

The total working area shall be checked on underground service plans and where required shall be scanned using an ADNOC Group approved Cable Avoidance Tool (CAT) to ascertain the presence of electrical cables and underground services. Before excavation work is carried out, it shall ensure a competent person assesses the work requirements for the site.  

Only Operators who have an authorized driving license and have been confirmed competent shall be allowed to operate earthmoving equipment; and

Excavation equipment shall always be guided by banks man/flag man who shall be aware of the movement and operation of heavy equipment.  

Where the excavation is to be greater than 1 metre width, scanning shall be carried out at both sides of the proposed excavation and at every 5 metres across the trench.   

IDENTIFICATION OF UNDERGROUND SERVICES & OVERHEAD POWER LINE  

Site survey shall be conducted to identify the presence of underground service and overhead power lines as part of planning.

Mechanical excavators should not be used when the presence of underground pipes, cables (electrical and telecommunications), vessels, or structures are known or expected within 3 meters (10 feet) of the excavation.   

Subject to the risks being adequately assessed, mechanical excavation can be undertaken up to a distance of 1m from pipe-work / structures. Using machinery for excavation within 3 meters from live hydrocarbon facility/ foundations or electrical cable will be considered Critical Work Activity.    

Insulated tools should be used for hand digging near electric cables.  

Adequate lighting shall be made available wherever required. And as a minimum the illumination should not be less than 200 lux. 

Specific Requirements for Trenches- Following are the  minimum requirements:

▪ It is required to provide ladders, steps, ramps or other safe means of egress for workers working in trench excavation deeper than 1.2 m.;  

▪ To cater for any emergency, means of egress shall be located every 7.62 meters (25 feet).  Pilot trenches shall always be dug using hand tools only in maximum depth steps of 1.2 meters (4 feet), relative to the adjacent ground level. Pilot trenches dug to a depth exceeding 1.2 meters are considered to be confined spaces and the rules around confined space entry apply.