Although recently a news cycle focal point, not all infrastructure requires winterization. Notwithstanding, the damage and publicity witnessed has many owners and operators asking an important question – when to winterize?
The extent of winterization needed for a facility is a balance of safety, economic, and likelihood of severe cold weather conditions. Typical protections include the elimination or minimization of dead legs in piping, heat trace & insulation, and shelters being included in design. Operational protections such as draining & maintenance procedures, circulation, and chemical injection are also solutions. Ultimately, the level of winterization right for a facility comes down to the minimum ambient design temperature based on climate and location considered with the safety and economic impacts during cold weather resulting from shutting down, infrastructure damage, and even off spec product.
Halker has compiled weather data from the National Oceanic and Atmospheric Administration for the Bakken and DJ basin as well as Corpus Christi from the last 15 years. The chart below shows the annual minimum temperature for each location based on daily minimum temperature readings from local weather stations in the area. 40°F is a typical minimum process temperature target. When ambient temperature falls below this line, the process fluid can be at risk of falling below the minimum design temperature.
Non-winterized facilities are at risk when ambient temperatures drop below freezing for an extended period. Facilities in locations that do not usually experience freezing temperatures are often most affected since risks in design and operation compound overtime without presenting serious problems. In such cases, adding insulation alone is very practical in moderate climates to mitigate freezing in standing lines. The addition of electric trace can offset 3-6 W/ft of heat loss from piping systems.
When considering winterization, the full scope and level required needs to be determined based on individual characteristics of the facility and equipment being winterized. Owners and operators should ensure winterization is considered early in a facilities design process for new infrastructure and is a focus for the Process Hazard Analysis (PHA). For existing unprotected facilities, minimal expense to winterize key systems will produce large returns in safety and profitability.