As mentioned previously, it has been assumed that installation in an area does not start until all 40 spools for that area are available. This is not necessarily industry practice (management pressure to start work and produce "show pipe" even though work cannot be executed optimally, usually is very high) but the line of balance labeled Area Done in Figure 3 (Left, Upper middle) confirms that accumulating a huge buffer makes it possible for the installation crew to achieve its highest possible production rate (also see Howell et al. 1993). At 20% of spools installed, nearly all spools have been delivered to site; vice versa, at 60% of spools delivered, barely any installation work has started (also see Figure 4 Top Left). For the crew, this will be an effective way of getting work done, provided that they need not be idle prior to starting to install.