Article 20 -  Extension of period of implementation of the tasks  Article 21 -  Delays in implementation of the tasks  c) submit to the project manager full and detailed particulars of the request, within 30  days from the above notification unless otherwise agreed between the contractor and  the supervisor, in order that such request may be investigated at the time.  b) If the contractor fails to give notice of a request for extension of the period of  implementation within such period of 15 days, the period of implementation shall  not be extended and the contracting authority shall be discharged from all liability in  connection with the request; and a) give notice to the project manager of its intention to make such a request no later  than 15 days after the contractor became aware, or should have become aware of the  event or circumstance giving rise to the request. h) any other causes referred to in these general conditions which are not due to the  contractor's default.  g) extra or additional supplies ordered by the contracting authority;  f) force majeure;  e) any suspension of the delivery and/or installation of the supplies which is not due  to the contractor's default;  d) failure of the contracting authority to fulfil its obligations under the contract;  c) administrative orders affecting the date of completion other than those arising from  the contractor's default;  b) artificial obstructions or physical conditions which may affect delivery of the  supplies, which could not reasonably have been foreseen by an experienced  contractor;  a) exceptional weather conditions in the country of the contracting authority which  may affect installation or erection of the supplies;  20.1. The contractor may request an extension to the period of implementation of the tasks if it  is or will be delayed in completing the contract by any of the following reasons:  August 2020 c4e_annexigc_en  Page 16 of 36  21.1. If the contractor fails to deliver any or all of the goods or perform the services within the  period of implementation of the tasks specified in the contract, the contracting authority  shall, without formal notice and without prejudice to its other remedies under the  contract, be entitled to liquidated damages for every day, or part thereof, which shall  elapse between the end of the period of implementation of the tasks, or extended period  of implementation of the tasks under article 20, and the actual date of completion. The  daily rate of liquidated damages is 5/1000 of the value of the undelivered supplies to a  maximum of 15% of the total contract price.  20.3. Within 30 days from the receipt of the contractor's detailed particulars of the request, the  project manager shall in agreement with the contracting authority, by notice to the  contractor, grant such extension of the period of implementation of the tasks as may be  justified, either prospectively or retrospectively, or inform the contractor that it is not  entitled to an extension.  20.2. If the contractor considers himself to be entitled to any extension of the period of  implementation under the contract, the contractor shall