Guild of Project Controls: Compendium | Roles | Assessment | Certifications | Membership

Tips on using this forum..

(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?

(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.

Question on Lag

3 replies [Last post]
Femi Ogunleye
User offline. Last seen 7 years 2 weeks ago. Offline
Joined: 9 Jan 2014
Posts: 6
Groups: None

What is the implication of using both positive and nagative lags on a programme and what are the benefits?

Replies

RAJASEKAR PT
User offline. Last seen 3 years 18 weeks ago. Offline
Joined: 17 Apr 2012
Posts: 3

Can i know the Weight of connection bolts required to erect the pipe racks and othe steel structures ?

Jessie Ramos
User offline. Last seen 7 years 43 weeks ago. Offline
Joined: 7 Dec 2013
Posts: 7
Groups: None

Hi everyone,

I would like to ask if what is the activity type of "SHOP DRAWING" when you make it as an activity, is this "Level of Effort" or "Task Dependent"...

Thanks

Patrick Weaver
User offline. Last seen 2 days 14 hours ago. Offline
Joined: 18 Jan 2001
Posts: 290
Groups: None

Negative lag is the same as a ‘lead’ and advances the scheduled start (or finish) of the successor.   Most authorities do not like ‘leads’ (eg, the DCMA 14 point check list: http://www.mosaicprojects.com.au/WhitePapers/WP1088_DCMA-14-Point.pdf ) However, particularly in high-level schedules and early in the schedule development cycle making the logical statement that ‘painting’ can start 2 weeks before the finish of ‘welding’ is reasonable if both activities are several months.  As the level of detail builds in the schedule real links can replace the ‘lead’.

Positive lags delay the successor activity and are generally accepted as useful provided the lag does not replace an activity. Lags can be used to represent administrative lead times, to manage work flows or to represent mandated drying, curing, setting times when nothing can happen.

Both need to be used with care and you need to understand how they are applied by your software (there’s no consistency).  For ore on this see: http://www.mosaicprojects.com.au/PDF/Links_Lags_Ladders.pdf