In Remove method I want to remove smallest array and less than 19 through for or while loop? how Can I do that


namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
 

            List<PipesList> lstPipeTypes = new List<PipesList>();

            lstPipeTypes.Add(new PipesList("PVC Pipes"));
            lstPipeTypes[0].Pipes.Add(new Pipe("The blue pipe", 12));
            lstPipeTypes[0].Pipes.Add(new Pipe("The red pipe", 15));
            lstPipeTypes[0].Pipes.Add(new Pipe("The silver pipe", 6));
            lstPipeTypes[0].Pipes.Add(new Pipe("The green pipe", 52));

            lstPipeTypes.Add(new PipesList("Iron Pipes"));
            lstPipeTypes[1].Pipes.Add(new Pipe("The gold pipe", 9));
            lstPipeTypes[1].Pipes.Add(new Pipe("The orange pipe", 115));
            lstPipeTypes[1].Pipes.Add(new Pipe("The pink pipe", 1));

            lstPipeTypes.Add(new PipesList("Chrome Pipes"));
            lstPipeTypes[2].Pipes.Add(new Pipe("The grey pipe", 12));
            lstPipeTypes[2].Pipes.Add(new Pipe("The black pipe", 15));
            lstPipeTypes[2].Pipes.Add(new Pipe("The white pipe", 19));
            lstPipeTypes[2].Pipes.Add(new Pipe("The brown pipe", 60));
            lstPipeTypes[2].Pipes.Add(new Pipe("The peach pipe", 16));


            lstPipeTypes = RemoveTheSmallPipes(lstPipeTypes);

            foreach (var pipeList in lstPipeTypes)
            {
                Console.WriteLine("PipesList: {0}", pipeList.pipeType);

                foreach (var pipe in pipeList.Pipes)
                {
                    Console.WriteLine("{0}, length: {1}", pipe.name, pipe.length);
                }
                Console.WriteLine();
            }

            Console.WriteLine("Done, press return to exit");
            Console.ReadLine();
        }


        public static List<PipesList> RemoveTheSmallPipes(List<PipesList> lstPipeTypes)
        {
            for (int i = 0; i < length; i++)
            {
                
            }
          
            //Place your code in here
            //It should remove all pipes that have lengths lower than 19.

            return lstPipeTypes;

        }
    }

    class PipesList
    {
        public string pipeType;
        public List<Pipe> Pipes;

        public PipesList(string newBoxType)
        {
            pipeType = newBoxType;
            Pipes = new List<Pipe>();
        }
    }

    class Pipe
    {
        public string name;
        public float length;

        public Pipe(string newName, float newLength)
        {
            this.name = newName;
            this.length = newLength;
        }
    }


}
 I am new in c# , I want RemoveTheSmallPipes is meant to get rid of all of the pipes with lengths less than 19. 
 Please add the code into this method to search through the ArrayList of PipeList, and remove the small pipes from them 
In Remove method I want to remove smallest array and less than 19 through for or while loop? how Can I do that
===



namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
 

            List<PipesList> lstPipeTypes = new List<PipesList>();

            lstPipeTypes.Add(new PipesList("PVC Pipes"));
            lstPipeTypes[0].Pipes.Add(new Pipe("The blue pipe", 12));
            lstPipeTypes[0].Pipes.Add(new Pipe("The red pipe", 15));
            lstPipeTypes[0].Pipes.Add(new Pipe("The silver pipe", 6));
            lstPipeTypes[0].Pipes.Add(new Pipe("The green pipe", 52));

            lstPipeTypes.Add(new PipesList("Iron Pipes"));
            lstPipeTypes[1].Pipes.Add(new Pipe("The gold pipe", 9));
            lstPipeTypes[1].Pipes.Add(new Pipe("The orange pipe", 115));
            lstPipeTypes[1].Pipes.Add(new Pipe("The pink pipe", 1));

            lstPipeTypes.Add(new PipesList("Chrome Pipes"));
            lstPipeTypes[2].Pipes.Add(new Pipe("The grey pipe", 12));
            lstPipeTypes[2].Pipes.Add(new Pipe("The black pipe", 15));
            lstPipeTypes[2].Pipes.Add(new Pipe("The white pipe", 19));
            lstPipeTypes[2].Pipes.Add(new Pipe("The brown pipe", 60));
            lstPipeTypes[2].Pipes.Add(new Pipe("The peach pipe", 16));


            lstPipeTypes = RemoveTheSmallPipes(lstPipeTypes);

            foreach (var pipeList in lstPipeTypes)
            {
                Console.WriteLine("PipesList: {0}", pipeList.pipeType);

                foreach (var pipe in pipeList.Pipes)
                {
                    Console.WriteLine("{0}, length: {1}", pipe.name, pipe.length);
                }
                Console.WriteLine();
            }

            Console.WriteLine("Done, press return to exit");
            Console.ReadLine();
        }


        public static List<PipesList> RemoveTheSmallPipes(List<PipesList> lstPipeTypes)
        {
            for (int i = 0; i < length; i++)
            {
                
            }
          
            //Place your code in here
            //It should remove all pipes that have lengths lower than 19.

            return lstPipeTypes;

        }
    }

    class PipesList
    {
        public string pipeType;
        public List<Pipe> Pipes;

        public PipesList(string newBoxType)
        {
            pipeType = newBoxType;
            Pipes = new List<Pipe>();
        }
    }

    class Pipe
    {
        public string name;
        public float length;

        public Pipe(string newName, float newLength)
        {
            this.name = newName;
            this.length = newLength;
        }
    }


}
 I am new in c# , I want RemoveTheSmallPipes is meant to get rid of all of the pipes with lengths less than 19. 
 Please add the code into this method to search through the ArrayList of PipeList, and remove the small pipes from them 