Whether, weather or wether

NEC3 and NEC4 Contracts
1

NEC 4 subcontract CE 60.1 (13). I have read the various Q&As on here, but I am still at a bit of a loss. We are carrying out a groundworks package and I have sourced the relevant weather reports.
The monthly summary for rainfall in May is 99.2mm, the 1 in 10 is 87.00 so the monthly value is greater than the 1-in-10 value so a CE I believe. However, the number of days with >5mm of rain is 4 compared with a 1-in-10 average of 6. What is the relevance of the >5mm measurement if any?
On the 21st May we had a whopping 59.9mm of rain which rained us off and we spent two days pumping out the excavations afterwards.

What is our entitlement - do we average the 1-in-10 across the month giving an expected rainfall per day or once it has been established as a CE do we cost accordingly based on actual cost?
Once the threshold is crossed how is it assessed?

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2

@WilliamBrown any advise for Paul?

3

Hi Paul,

I sympathise with you here. In my view this part of the NEC can be difficult to apply and is open to interpretation. The wording of this clause can also lead to some odd, but contractually correct, results. If there was ever a clause that requires the parties to sit down and be sensible, it is this one.

Cumulative rainfall

On the first part of your question, the weather CE under clause 60.1(13) is triggered if any of the weather measurements listed in the Contract Data exceed the 1-in-10 year threshold. There are four of these in the standard contract:

(1) cumulative rainfall (mm)
(2) number of days with rainfall >5mm
(3) number of days with minimum air temperature <0 degrees C
(4) number of days with snow lying at a set time of day

In your case, weather measurement (1) has been triggered because the “monthly summary” figure of 99.2mm exceeds the monthly cumulative figure of 87mm. You don’t need to do any averaging to arrive at this conclusion. It is a CE.

The tricky bit with the weather measurement above, is the final paragraph of clause 60.1(13), which says that you are only entitled to the difference between the 1-in-10 year figure (in this case 87mm) and the recorded figure (in this case 99.2mm). Proving what the difference in Defined Cost is between having 87mm of rain, and 99.2mm of rain will be difficult - if not impossible. You need to carefully think through how you would present this.

In principle, you would be able to claim the likes of additional pumping out, days that you are rained off etc, but only of this is over and above what you would have suffered had the average rainfall been 87mm. Again, this will be hard to prove.

Number of days with rainfall >5mm

On the facts you have presented, clause 60.1(13) would not be separately triggered by weather measurement (2) exceeding the 1-in-10 year threshold of 6 days.

As such, you have no entitlement to the 2 days you spent pumping out the excavations due to the 59.9mm of rain on 21 May. You are deemed to have allowed for rainfall of >5mm on up to six days in May. Unfortunately there is not a separate weather measurement for rain exceeding a 1-in-10 year threshold on a given day. 59.9mm on a single day sounds worse than a 1-in-10 year event to me, but this measurement simply is not listed in the Contract Data.

If there was rain >5mm on say 10, 11, 13, 14, 15 and 16 May, then you would be entitled to all of the effects of the 59.9mm on 21 May. But not the case here.

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